Guide to the Secure Configuration of Oracle Linux 8

with profile Health Insurance Portability and Accountability Act (HIPAA)
The HIPAA Security Rule establishes U.S. national standards to protect individuals’ electronic personal health information that is created, received, used, or maintained by a covered entity. The Security Rule requires appropriate administrative, physical and technical safeguards to ensure the confidentiality, integrity, and security of electronic protected health information. This profile configures Oracle Linux 8 to the HIPAA Security Rule identified for securing of electronic protected health information.
This guide presents a catalog of security-relevant configuration settings for Oracle Linux 8. It is a rendering of content structured in the eXtensible Configuration Checklist Description Format (XCCDF) in order to support security automation. The SCAP content is is available in the scap-security-guide package which is developed at https://www.open-scap.org/security-policies/scap-security-guide.

Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG, which provides required settings for US Department of Defense systems, is one example of a baseline created from this guidance.
Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.

Profile Information

Profile TitleHealth Insurance Portability and Accountability Act (HIPAA)
Profile IDxccdf_org.ssgproject.content_profile_hipaa

CPE Platforms

  • cpe:/o:oracle:linux:8

Revision History

Current version: 0.1.51

  • draft (as of 2020-07-20)

Table of Contents

  1. System Settings
    1. Account and Access Control
    2. System Accounting with auditd
    3. Installing and Maintaining Software
    4. GRUB2 bootloader configuration
    5. File Permissions and Masks
    6. SELinux
    7. Network Configuration and Firewalls
    8. Configure Syslog
  2. Services
    1. Cron and At Daemons
    2. Network Routing
    3. SSH Server
    4. Obsolete Services
    5. Base Services
    6. NFS and RPC

Checklist

Group   Guide to the Secure Configuration of Oracle Linux 8   Group contains 52 groups and 140 rules
Group   System Settings   Group contains 37 groups and 113 rules

[ref]   Contains rules that check correct system settings.

Group   Account and Access Control   Group contains 4 groups and 9 rules

[ref]   In traditional Unix security, if an attacker gains shell access to a certain login account, they can perform any action or access any file to which that account has access. Therefore, making it more difficult for unauthorized people to gain shell access to accounts, particularly to privileged accounts, is a necessary part of securing a system. This section introduces mechanisms for restricting access to accounts under Oracle Linux 8.

Group   Protect Accounts by Restricting Password-Based Login   Group contains 2 groups and 4 rules

[ref]   Conventionally, Unix shell accounts are accessed by providing a username and password to a login program, which tests these values for correctness using the /etc/passwd and /etc/shadow files. Password-based login is vulnerable to guessing of weak passwords, and to sniffing and man-in-the-middle attacks against passwords entered over a network or at an insecure console. Therefore, mechanisms for accessing accounts by entering usernames and passwords should be restricted to those which are operationally necessary.

Group   Verify Proper Storage and Existence of Password Hashes   Group contains 1 rule

[ref]   By default, password hashes for local accounts are stored in the second field (colon-separated) in /etc/shadow. This file should be readable only by processes running with root credentials, preventing users from casually accessing others' password hashes and attempting to crack them. However, it remains possible to misconfigure the system and store password hashes in world-readable files such as /etc/passwd, or to even store passwords themselves in plaintext on the system. Using system-provided tools for password change/creation should allow administrators to avoid such misconfiguration.

Rule   Prevent Login to Accounts With Empty Password   [ref]

If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. Remove any instances of the nullok option in /etc/pam.d/system-auth to prevent logins with empty passwords.

Rationale:

If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_no_empty_passwords
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(1)(a), IA-5(c), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, FIA_AFL.1, Req-8.2.3, SRG-OS-000480-GPOS-00227



sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/system-auth
sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/password-auth


Complexity:low
Disruption:medium
Strategy:configure
- name: Prevent Log In to Accounts With Empty Password - system-auth
  replace:
    dest: /etc/pam.d/system-auth
    follow: true
    regexp: nullok
  tags:
    - CJIS-5.5.2
    - NIST-800-171-3.1.1
    - NIST-800-171-3.1.5
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IA-5(1)(a)
    - NIST-800-53-IA-5(c)
    - PCI-DSS-Req-8.2.3
    - configure_strategy
    - high_severity
    - low_complexity
    - medium_disruption
    - no_empty_passwords
    - no_reboot_needed

- name: Prevent Log In to Accounts With Empty Password - password-auth
  replace:
    dest: /etc/pam.d/password-auth
    follow: true
    regexp: nullok
  tags:
    - CJIS-5.5.2
    - NIST-800-171-3.1.1
    - NIST-800-171-3.1.5
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IA-5(1)(a)
    - NIST-800-53-IA-5(c)
    - PCI-DSS-Req-8.2.3
    - configure_strategy
    - high_severity
    - low_complexity
    - medium_disruption
    - no_empty_passwords
    - no_reboot_needed


apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
        filesystem: root
        mode: 0644
        path: /etc/pam.d/password-auth
      - contents:
          source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
        filesystem: root
        mode: 0644
        path: /etc/pam.d/system-auth
Group   Restrict Root Logins   Group contains 3 rules

[ref]   Direct root logins should be allowed only for emergency use. In normal situations, the administrator should access the system via a unique unprivileged account, and then use su or sudo to execute privileged commands. Discouraging administrators from accessing the root account directly ensures an audit trail in organizations with multiple administrators. Locking down the channels through which root can connect directly also reduces opportunities for password-guessing against the root account. The login program uses the file /etc/securetty to determine which interfaces should allow root logins. The virtual devices /dev/console and /dev/tty* represent the system consoles (accessible via the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default installation). The default securetty file also contains /dev/vc/*. These are likely to be deprecated in most environments, but may be retained for compatibility. Root should also be prohibited from connecting via network protocols. Other sections of this document include guidance describing how to prevent root from logging in via SSH.

Rule   Restrict Serial Port Root Logins   [ref]

To restrict root logins on serial ports, ensure lines of this form do not appear in /etc/securetty:

ttyS0
ttyS1

Rationale:

Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_restrict_serial_port_logins
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.1, 3.1.5, CCI-000770, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6, CM-6(a), PR.AC-4, PR.DS-5



sed -i '/ttyS/d' /etc/securetty


Complexity:low
Disruption:low
Strategy:restrict
- name: Restrict Serial Port Root Logins
  lineinfile:
    dest: /etc/securetty
    regexp: ttyS[0-9]
    state: absent
  tags:
    - NIST-800-171-3.1.1
    - NIST-800-171-3.1.5
    - NIST-800-53-AC-6
    - NIST-800-53-CM-6(a)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_serial_port_logins
    - restrict_strategy

Rule   Direct root Logins Not Allowed   [ref]

To further limit access to the root account, administrators can disable root logins at the console by editing the /etc/securetty file. This file lists all devices the root user is allowed to login to. If the file does not exist at all, the root user can login through any communication device on the system, whether via the console or via a raw network interface. This is dangerous as user can login to the system as root via Telnet, which sends the password in plain text over the network. By default, Oracle Linux 8's /etc/securetty file only allows the root user to login at the console physically attached to the system. To prevent root from logging in, remove the contents of this file. To prevent direct root logins, remove the contents of this file by typing the following command:

$ sudo echo > /etc/securetty

Rationale:

Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This is required for FISMA Low and FISMA Moderate systems.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_no_direct_root_logins
Identifiers and References

References:  NT28(R19), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.1, 3.1.6, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-2, CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7



echo > /etc/securetty


Complexity:low
Disruption:low
Strategy:restrict
- name: Direct root Logins Not Allowed
  copy:
    dest: /etc/securetty
    content: ''
  tags:
    - NIST-800-171-3.1.1
    - NIST-800-171-3.1.6
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IA-2
    - low_complexity
    - low_disruption
    - medium_severity
    - no_direct_root_logins
    - no_reboot_needed
    - restrict_strategy
Group   Protect Physical Console Access   Group contains 5 rules

[ref]   It is impossible to fully protect a system from an attacker with physical access, so securing the space in which the system is located should be considered a necessary step. However, there are some steps which, if taken, make it more difficult for an attacker to quickly or undetectably modify a system from its console.

Rule   Disable debug-shell SystemD Service   [ref]

SystemD's debug-shell service is intended to diagnose SystemD related boot issues with various systemctl commands. Once enabled and following a system reboot, the root shell will be available on tty9 which is access by pressing CTRL-ALT-F9. The debug-shell service should only be used for SystemD related issues and should otherwise be disabled.

By default, the debug-shell SystemD service is already disabled. The debug-shell service can be disabled with the following command:

$ sudo systemctl disable debug-shell.service
The debug-shell service can be masked with the following command:
$ sudo systemctl mask debug-shell.service

Rationale:

This prevents attackers with physical access from trivially bypassing security on the machine through valid troubleshooting configurations and gaining root access when the system is rebooted.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_service_debug-shell_disabled
Identifiers and References

References:  3.4.5, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), FIA_AFL.1, SRG-OS-000324-GPOS-00125



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'debug-shell.service'
"$SYSTEMCTL_EXEC" disable 'debug-shell.service'
"$SYSTEMCTL_EXEC" mask 'debug-shell.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^debug-shell.socket'; then
    "$SYSTEMCTL_EXEC" stop 'debug-shell.socket'
    "$SYSTEMCTL_EXEC" disable 'debug-shell.socket'
    "$SYSTEMCTL_EXEC" mask 'debug-shell.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'debug-shell.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service debug-shell
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service debug-shell
      systemd:
        name: debug-shell.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"debug-shell.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_debug-shell_disabled

- name: Unit Socket Exists - debug-shell.socket
  command: systemctl list-unit-files debug-shell.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_debug-shell_disabled

- name: Disable socket debug-shell
  systemd:
    name: debug-shell.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"debug-shell.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_debug-shell_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_debug-shell

class disable_debug-shell {
  service {'debug-shell':
    enable => false,
    ensure => 'stopped',
  }
}

Rule   Disable Ctrl-Alt-Del Reboot Activation   [ref]

By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed.

To configure the system to ignore the Ctrl-Alt-Del key sequence from the command line instead of rebooting the system, do either of the following:

ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target
or
systemctl mask ctrl-alt-del.target


Do not simply delete the /usr/lib/systemd/system/ctrl-alt-del.service file, as this file may be restored during future system updates.

Warning:  Disabling the Ctrl-Alt-Del key sequence in /etc/init/control-alt-delete.conf DOES NOT disable the Ctrl-Alt-Del key sequence if running in runlevel 6 (e.g. in GNOME, KDE, etc.)! The Ctrl-Alt-Del key sequence will only be disabled if running in the non-graphical runlevel 3.
Rationale:

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_reboot
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227



systemctl mask ctrl-alt-del.target


Complexity:low
Disruption:low
Strategy:disable
- name: Disable Ctrl-Alt-Del Reboot Activation
  systemd:
    name: ctrl-alt-del.target
    masked: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - disable_ctrlaltdel_reboot
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed

Rule   Require Authentication for Single User Mode   [ref]

Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup. By default, no authentication is performed if single-user mode is selected.

By default, single-user mode is protected by requiring a password and is set in /usr/lib/systemd/system/rescue.service.

Rationale:

This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_require_singleuser_auth
Identifiers and References

References:  1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-2, AC-3, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_AFL.1, SRG-OS-000080-GPOS-00048




service_file="/usr/lib/systemd/system/rescue.service"

sulogin="/usr/lib/systemd/systemd-sulogin-shell rescue"

if grep "^ExecStart=.*" "$service_file" ; then
    sed -i "s%^ExecStart=.*%ExecStart=-$sulogin%" "$service_file"
else
    echo "ExecStart=-$sulogin" >> "$service_file"
fi


Complexity:low
Disruption:low
Strategy:restrict
- name: require single user mode password
  lineinfile:
    create: true
    dest: /usr/lib/systemd/system/rescue.service
    regexp: ^#?ExecStart=
    line: ExecStart=-/usr/lib/systemd/systemd-sulogin-shell rescue
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.1
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-3
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IA-2
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - require_singleuser_auth
    - restrict_strategy

Rule   Verify that Interactive Boot is Disabled   [ref]

Oracle Linux 8 systems support an "interactive boot" option that can be used to prevent services from being started. On a Oracle Linux 8 system, interactive boot can be enabled by providing a 1, yes, true, or on value to the systemd.confirm_spawn kernel argument in /etc/default/grub. Remove any instance of

systemd.confirm_spawn=(1|yes|true|on)
from the kernel arguments in that file to disable interactive boot. It is also required to change the runtime configuration, run:
/sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"

Rationale:

Using interactive boot, the console user could disable auditing, firewalls, or other services, weakening system security.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_grub2_disable_interactive_boot
Identifiers and References

References:  11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.2, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, SC-2(1), CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_AFL.1, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:low
Reboot:true
Strategy:restrict

CONFIRM_SPAWN_YES="systemd.confirm_spawn=\(1\|yes\|true\|on\)"
CONFIRM_SPAWN_NO="systemd.confirm_spawn=no"

if grep -q "\(GRUB_CMDLINE_LINUX\|GRUB_CMDLINE_LINUX_DEFAULT\)" /etc/default/grub
then
	sed -i "s/${CONFIRM_SPAWN_YES}/${CONFIRM_SPAWN_NO}/" /etc/default/grub
fi
# Remove 'systemd.confirm_spawn' kernel argument also from runtime settings
/sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Verify that Interactive Boot is Disabled in /etc/default/grub
  replace:
    dest: /etc/default/grub
    regexp: systemd.confirm_spawn=(1|yes|true|on)
    replace: systemd.confirm_spawn=no
  tags:
    - NIST-800-171-3.1.2
    - NIST-800-171-3.4.5
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-2(1)
    - grub2_disable_interactive_boot
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Verify that Interactive Boot is Disabled (runtime)
  command: /sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"
  tags:
    - NIST-800-171-3.1.2
    - NIST-800-171-3.4.5
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-2(1)
    - grub2_disable_interactive_boot
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Disable Ctrl-Alt-Del Burst Action   [ref]

By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed Ctrl-Alt-Delete more than 7 times in 2 seconds.

To configure the system to ignore the CtrlAltDelBurstAction setting, add or modify the following to /etc/systemd/system.conf:

CtrlAltDelBurstAction=none

Warning:  Disabling the Ctrl-Alt-Del key sequence in /etc/init/control-alt-delete.conf DOES NOT disable the Ctrl-Alt-Del key sequence if running in runlevel 6 (e.g. in GNOME, KDE, etc.)! The Ctrl-Alt-Del key sequence will only be disabled if running in the non-graphical runlevel 3.
Rationale:

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_burstaction
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), CM-6(a), PR.AC-4, PR.DS-5, SRG-OS-000324-GPOS-00125



# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/systemd/system.conf' '^CtrlAltDelBurstAction=' 'none' '' '%s=%s'


Complexity:low
Disruption:low
Strategy:disable
- name: Disable Ctrl-Alt-Del Burst Action
  lineinfile:
    dest: /etc/systemd/system.conf
    state: present
    regexp: ^CtrlAltDelBurstAction
    line: CtrlAltDelBurstAction=none
    create: true
  tags:
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-6(a)
    - disable_ctrlaltdel_burstaction
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
Group   System Accounting with auditd   Group contains 10 groups and 70 rules

[ref]   The audit service provides substantial capabilities for recording system activities. By default, the service audits about SELinux AVC denials and certain types of security-relevant events such as system logins, account modifications, and authentication events performed by programs such as sudo. Under its default configuration, auditd has modest disk space requirements, and should not noticeably impact system performance.

NOTE: The Linux Audit daemon auditd can be configured to use the augenrules program to read audit rules files (*.rules) located in /etc/audit/rules.d location and compile them to create the resulting form of the /etc/audit/audit.rules configuration file during the daemon startup (default configuration). Alternatively, the auditd daemon can use the auditctl utility to read audit rules from the /etc/audit/audit.rules configuration file during daemon startup, and load them into the kernel. The expected behavior is configured via the appropriate ExecStartPost directive setting in the /usr/lib/systemd/system/auditd.service configuration file. To instruct the auditd daemon to use the augenrules program to read audit rules (default configuration), use the following setting:

ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file. In order to instruct the auditd daemon to use the auditctl utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file. Refer to [Service] section of the /usr/lib/systemd/system/auditd.service configuration file for further details.

Government networks often have substantial auditing requirements and auditd can be configured to meet these requirements. Examining some example audit records demonstrates how the Linux audit system satisfies common requirements. The following example from Fedora Documentation available at https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/SELinux_Users_and_Administrators_Guide/sect-Security-Enhanced_Linux-Troubleshooting-Fixing_Problems.html#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages shows the substantial amount of information captured in a two typical "raw" audit messages, followed by a breakdown of the most important fields. In this example the message is SELinux-related and reports an AVC denial (and the associated system call) that occurred when the Apache HTTP Server attempted to access the /var/www/html/file1 file (labeled with the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
  • msg=audit(1226874073.147:96)
    • The number in parentheses is the unformatted time stamp (Epoch time) for the event, which can be converted to standard time by using the date command.
  • { getattr }
    • The item in braces indicates the permission that was denied. getattr indicates the source process was trying to read the target file's status information. This occurs before reading files. This action is denied due to the file being accessed having the wrong label. Commonly seen permissions include getattr, read, and write.
  • comm="httpd"
    • The executable that launched the process. The full path of the executable is found in the exe= section of the system call (SYSCALL) message, which in this case, is exe="/usr/sbin/httpd".
  • path="/var/www/html/file1"
    • The path to the object (target) the process attempted to access.
  • scontext="unconfined_u:system_r:httpd_t:s0"
    • The SELinux context of the process that attempted the denied action. In this case, it is the SELinux context of the Apache HTTP Server, which is running in the httpd_t domain.
  • tcontext="unconfined_u:object_r:samba_share_t:s0"
    • The SELinux context of the object (target) the process attempted to access. In this case, it is the SELinux context of file1. Note: the samba_share_t type is not accessible to processes running in the httpd_t domain.
  • From the system call (SYSCALL) message, two items are of interest:
    • success=no: indicates whether the denial (AVC) was enforced or not. success=no indicates the system call was not successful (SELinux denied access). success=yes indicates the system call was successful - this can be seen for permissive domains or unconfined domains, such as initrc_t and kernel_t.
    • exe="/usr/sbin/httpd": the full path to the executable that launched the process, which in this case, is exe="/usr/sbin/httpd".

Group   Configure auditd Data Retention   Group contains 2 rules

[ref]   The audit system writes data to /var/log/audit/audit.log. By default, auditd rotates 5 logs by size (6MB), retaining a maximum of 30MB of data in total, and refuses to write entries when the disk is too full. This minimizes the risk of audit data filling its partition and impacting other services. This also minimizes the risk of the audit daemon temporarily disabling the system if it cannot write audit log (which it can be configured to do). For a busy system or a system which is thoroughly auditing system activity, the default settings for data retention may be insufficient. The log file size needed will depend heavily on what types of events are being audited. First configure auditing to log all the events of interest. Then monitor the log size manually for awhile to determine what file size will allow you to keep the required data for the correct time period.

Using a dedicated partition for /var/log/audit prevents the auditd logs from disrupting system functionality if they fill, and, more importantly, prevents other activity in /var from filling the partition and stopping the audit trail. (The audit logs are size-limited and therefore unlikely to grow without bound unless configured to do so.) Some machines may have requirements that no actions occur which cannot be audited. If this is the case, then auditd can be configured to halt the machine if it runs out of space. Note: Since older logs are rotated, configuring auditd this way does not prevent older logs from being rotated away before they can be viewed. If your system is configured to halt when logging cannot be performed, make sure this can never happen under normal circumstances! Ensure that /var/log/audit is on its own partition, and that this partition is larger than the maximum amount of data auditd will retain normally.

Rule   Configure auditd to use audispd's syslog plugin   [ref]

To configure the auditd service to use the syslog plug-in of the audispd audit event multiplexor, set the active line in /etc/audit/plugins.d/syslog.conf to yes. Restart the auditd service:

$ sudo service auditd restart

Rationale:

The auditd service does not include the ability to send audit records to a centralized server for management directly. It does, however, include a plug-in for audit event multiplexor (audispd) to pass audit records to the local syslog server

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_auditd_audispd_syslog_plugin_activated
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000136, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, AU-4(1), CM-6(a), DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.3, SRG-OS-000479-GPOS-00224, SRG-OS-000342-GPOS-00133, SRG-OS-000051-VMM-000230, SRG-OS-000058-VMM-000270, SRG-OS-000059-VMM-000280, SRG-OS-000479-VMM-001990, SRG-OS-000479-VMM-001990




var_syslog_active="yes"


AUDISP_SYSLOGCONFIG=/etc/audit/plugins.d/syslog.conf
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append $AUDISP_SYSLOGCONFIG '^active' "$var_syslog_active" ""


Complexity:low
Disruption:low
Strategy:configure
- name: enable syslog plugin
  lineinfile:
    dest: /etc/audit/plugins.d/syslog.conf
    regexp: ^active
    line: active = yes
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-53-AU-4(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.3
    - auditd_audispd_syslog_plugin_activated
    - configure_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

Rule   Configure auditd flush priority   [ref]

The auditd service can be configured to synchronously write audit event data to disk. Add or correct the following line in /etc/audit/auditd.conf to ensure that audit event data is fully synchronized with the log files on the disk:

flush = data

Rationale:

Audit data should be synchronously written to disk to ensure log integrity. These parameters assure that all audit event data is fully synchronized with the log files on the disk.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_auditd_data_retention_flush
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001576, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-11, CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000480-GPOS-00227




var_auditd_flush="data"

AUDITCONFIG=/etc/audit/auditd.conf

# if flush is present, flush param edited to var_auditd_flush
# else flush param is defined by var_auditd_flush
#
# the freq param is only used for values 'incremental' and 'incremental_async' and will be
# commented out if flush != incremental or flush != incremental_async
#
# if flush == incremental or flush == incremental_async && freq param is not defined, it 
# will be defined as the package-default value of 20

grep -q ^flush $AUDITCONFIG && \
  sed -i 's/^flush.*/flush = '"$var_auditd_flush"'/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
  echo "flush = $var_auditd_flush" >> $AUDITCONFIG
fi

if ! [ "$var_auditd_flush" == "incremental" ] && ! [ "$var_auditd_flush" == "incremental_async" ]; then
  sed -i 's/^freq/##freq/g' $AUDITCONFIG
elif [ "$var_auditd_flush" == "incremental" ] || [ "$var_auditd_flush" == "incremental_async" ]; then
  grep -q freq $AUDITCONFIG && \
    sed -i 's/^#\+freq/freq/g' $AUDITCONFIG
  if ! [ $? -eq 0 ]; then
    echo "freq = 20" >> $AUDITCONFIG
  fi
fi


Complexity:low
Disruption:low
Strategy:restrict
- name: XCCDF Value var_auditd_flush # promote to variable
  set_fact:
    var_auditd_flush: !!str data
  tags:
    - always

- name: Configure auditd Flush Priority
  lineinfile:
    dest: /etc/audit/auditd.conf
    regexp: ^\s*flush\s*=\s*.*$
    line: flush = {{ var_auditd_flush }}
    state: present
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.3.1
    - NIST-800-53-AU-11
    - NIST-800-53-CM-6(a)
    - auditd_data_retention_flush
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
Group   Configure auditd Rules for Comprehensive Auditing   Group contains 8 groups and 66 rules

[ref]   The auditd program can perform comprehensive monitoring of system activity. This section describes recommended configuration settings for comprehensive auditing, but a full description of the auditing system's capabilities is beyond the scope of this guide. The mailing list linux-audit@redhat.com exists to facilitate community discussion of the auditing system.

The audit subsystem supports extensive collection of events, including:

  • Tracing of arbitrary system calls (identified by name or number) on entry or exit.
  • Filtering by PID, UID, call success, system call argument (with some limitations), etc.
  • Monitoring of specific files for modifications to the file's contents or metadata.

Auditing rules at startup are controlled by the file /etc/audit/audit.rules. Add rules to it to meet the auditing requirements for your organization. Each line in /etc/audit/audit.rules represents a series of arguments that can be passed to auditctl and can be individually tested during runtime. See documentation in /usr/share/doc/audit-VERSION and in the related man pages for more details.

If copying any example audit rulesets from /usr/share/doc/audit-VERSION, be sure to comment out the lines containing arch= which are not appropriate for your system's architecture. Then review and understand the following rules, ensuring rules are activated as needed for the appropriate architecture.

After reviewing all the rules, reading the following sections, and editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart

Group   Record Unauthorized Access Attempts Events to Files (unsuccessful)   Group contains 6 rules

[ref]   At a minimum, the audit system should collect unauthorized file accesses for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules:

-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rule   Record Unsuccessful Access Attempts to Files - openat   [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_openat
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000392-GPOS-00172, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830



function create_audit_remediation_unsuccessful_file_modification_detailed {
	mkdir -p "$(dirname "$1")"
	# The - option to mark a here document limit string (<<-EOF) suppresses leading tabs (but not spaces) in the output.
	cat <<-EOF > "$1"
		## This content is a section of an Audit config snapshot recommended for linux systems that target OSPP compliance.
		## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

		## The purpose of these rules is to meet the requirements for Operating
		## System Protection Profile (OSPP)v4.2. These rules depends on having
		## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

		## Unsuccessful file creation (open with O_CREAT)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

		## Unsuccessful file modifications (open for write or truncate)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

		## Unsuccessful file access (any other opens) This has to go last.
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
	EOF
}
create_audit_remediation_unsuccessful_file_modification_detailed /etc/audit/rules.d/30-ospp-v42-remediation.rules


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit openat tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_openat
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/access.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/access.rules
  when:
    - find_openat.matched is defined and find_openat.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_openat.files | map(attribute=''path'') | list | first }}'
  when:
    - find_openat.matched is defined and find_openat.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the openat rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the openat rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the openat rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the openat rule in audit.rules when on x86_64
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_openat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Unsuccessful Access Attempts to Files - open   [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_open
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000392-GPOS-00172, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830



function create_audit_remediation_unsuccessful_file_modification_detailed {
	mkdir -p "$(dirname "$1")"
	# The - option to mark a here document limit string (<<-EOF) suppresses leading tabs (but not spaces) in the output.
	cat <<-EOF > "$1"
		## This content is a section of an Audit config snapshot recommended for linux systems that target OSPP compliance.
		## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

		## The purpose of these rules is to meet the requirements for Operating
		## System Protection Profile (OSPP)v4.2. These rules depends on having
		## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

		## Unsuccessful file creation (open with O_CREAT)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

		## Unsuccessful file modifications (open for write or truncate)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

		## Unsuccessful file access (any other opens) This has to go last.
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
	EOF
}
create_audit_remediation_unsuccessful_file_modification_detailed /etc/audit/rules.d/30-ospp-v42-remediation.rules


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit open tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_open
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/access.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/access.rules
  when:
    - find_open.matched is defined and find_open.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_open.files | map(attribute=''path'') | list | first }}'
  when:
    - find_open.matched is defined and find_open.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open rule in audit.rules when on x86_64
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Unsuccessful Access Attempts to Files - open_by_handle_at   [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_open_by_handle_at
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000392-GPOS-00172, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830



function create_audit_remediation_unsuccessful_file_modification_detailed {
	mkdir -p "$(dirname "$1")"
	# The - option to mark a here document limit string (<<-EOF) suppresses leading tabs (but not spaces) in the output.
	cat <<-EOF > "$1"
		## This content is a section of an Audit config snapshot recommended for linux systems that target OSPP compliance.
		## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

		## The purpose of these rules is to meet the requirements for Operating
		## System Protection Profile (OSPP)v4.2. These rules depends on having
		## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

		## Unsuccessful file creation (open with O_CREAT)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

		## Unsuccessful file modifications (open for write or truncate)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

		## Unsuccessful file access (any other opens) This has to go last.
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
	EOF
}
create_audit_remediation_unsuccessful_file_modification_detailed /etc/audit/rules.d/30-ospp-v42-remediation.rules


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit open_by_handle_at tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_open_by_handle_at
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/access.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/access.rules
  when:
    - find_open_by_handle_at.matched is defined and find_open_by_handle_at.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_open_by_handle_at.files | map(attribute=''path'') | list | first
        }}'
  when:
    - find_open_by_handle_at.matched is defined and find_open_by_handle_at.matched
      > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open_by_handle_at rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EACCES -F auid>=1000
      -F auid!=unset -F key=access
    - -a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EPERM -F auid>=1000
      -F auid!=unset -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open_by_handle_at rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EACCES -F auid>=1000
      -F auid!=unset -F key=access
    - -a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EPERM -F auid>=1000
      -F auid!=unset -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open_by_handle_at rule in /etc/audit/audit.rules when
    on x86
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EACCES -F auid>=1000
      -F auid!=unset -F key=access
    - -a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EPERM -F auid>=1000
      -F auid!=unset -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the open_by_handle_at rule in audit.rules when on x86_64
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EACCES -F auid>=1000
      -F auid!=unset -F key=access
    - -a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EPERM -F auid>=1000
      -F auid!=unset -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_open_by_handle_at
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Unsuccessful Access Attempts to Files - truncate   [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_truncate
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000392-GPOS-00172, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830



function create_audit_remediation_unsuccessful_file_modification_detailed {
	mkdir -p "$(dirname "$1")"
	# The - option to mark a here document limit string (<<-EOF) suppresses leading tabs (but not spaces) in the output.
	cat <<-EOF > "$1"
		## This content is a section of an Audit config snapshot recommended for linux systems that target OSPP compliance.
		## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

		## The purpose of these rules is to meet the requirements for Operating
		## System Protection Profile (OSPP)v4.2. These rules depends on having
		## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

		## Unsuccessful file creation (open with O_CREAT)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

		## Unsuccessful file modifications (open for write or truncate)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

		## Unsuccessful file access (any other opens) This has to go last.
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
	EOF
}
create_audit_remediation_unsuccessful_file_modification_detailed /etc/audit/rules.d/30-ospp-v42-remediation.rules


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit truncate tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_truncate
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/access.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/access.rules
  when:
    - find_truncate.matched is defined and find_truncate.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_truncate.files | map(attribute=''path'') | list | first }}'
  when:
    - find_truncate.matched is defined and find_truncate.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the truncate rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the truncate rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the truncate rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the truncate rule in audit.rules when on x86_64
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_truncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Unsuccessful Access Attempts to Files - ftruncate   [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exiu=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_ftruncate
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000392-GPOS-00172, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830



function create_audit_remediation_unsuccessful_file_modification_detailed {
	mkdir -p "$(dirname "$1")"
	# The - option to mark a here document limit string (<<-EOF) suppresses leading tabs (but not spaces) in the output.
	cat <<-EOF > "$1"
		## This content is a section of an Audit config snapshot recommended for linux systems that target OSPP compliance.
		## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

		## The purpose of these rules is to meet the requirements for Operating
		## System Protection Profile (OSPP)v4.2. These rules depends on having
		## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

		## Unsuccessful file creation (open with O_CREAT)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

		## Unsuccessful file modifications (open for write or truncate)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

		## Unsuccessful file access (any other opens) This has to go last.
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
	EOF
}
create_audit_remediation_unsuccessful_file_modification_detailed /etc/audit/rules.d/30-ospp-v42-remediation.rules


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit ftruncate tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_ftruncate
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/access.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/access.rules
  when:
    - find_ftruncate.matched is defined and find_ftruncate.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_ftruncate.files | map(attribute=''path'') | list | first }}'
  when:
    - find_ftruncate.matched is defined and find_ftruncate.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the ftruncate rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the ftruncate rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: '{{ item }}'
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the ftruncate rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the ftruncate rule in audit.rules when on x86_64
  lineinfile:
    line: '{{ item }}'
    state: present
    dest: /etc/audit/audit.rules
    create: true
  with_items:
    - -a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset
      -F key=access
    - -a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset
      -F key=access
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_ftruncate
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Unsuccessful Access Attempts to Files - creat   [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_creat
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000392-GPOS-00172, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830



function create_audit_remediation_unsuccessful_file_modification_detailed {
	mkdir -p "$(dirname "$1")"
	# The - option to mark a here document limit string (<<-EOF) suppresses leading tabs (but not spaces) in the output.
	cat <<-EOF > "$1"
		## This content is a section of an Audit config snapshot recommended for linux systems that target OSPP compliance.
		## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

		## The purpose of these rules is to meet the requirements for Operating
		## System Protection Profile (OSPP)v4.2. These rules depends on having
		## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

		## Unsuccessful file creation (open with O_CREAT)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
		-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

		## Unsuccessful file modifications (open for write or truncate)
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
		-a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

		## Unsuccessful file access (any other opens) This has to go last.
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
		-a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
	EOF
}
create_audit_remediation_unsuccessful_file_modification_detailed /etc/audit/rules.d/30-ospp-v42-remediation.rules


Complexity:low
Disruption:low
Strategy:restrict
- name: Add unsuccessful file operations audit rules
  blockinfile:
    path: /etc/audit/rules.d/30-ospp-v42-remediation.rules
    create: true
    block: |-
      ## This content is a section of an Audit config snapshot recommended for Oracle Linux 8 systems that target OSPP compliance.
      ## The following content has been retreived on 2019-03-11 from: https://github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules

      ## The purpose of these rules is to meet the requirements for Operating
      ## System Protection Profile (OSPP)v4.2. These rules depends on having
      ## 10-base-config.rules, 11-loginuid.rules, and 43-module-load.rules installed.

      ## Unsuccessful file creation (open with O_CREAT)
      -a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b32 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b64 -S open -F a1&0100 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create
      -a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-create

      ## Unsuccessful file modifications (open for write or truncate)
      -a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b32 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b64 -S openat,open_by_handle_at -F a2&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b32 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b64 -S open -F a1&01003 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b32 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification
      -a always,exit -F arch=b64 -S truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-modification

      ## Unsuccessful file access (any other opens) This has to go last.
      -a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
      -a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
      -a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
      -a always,exit -F arch=b64 -S open,creat,truncate,ftruncate,openat,open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccesful-access
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.1
    - PCI-DSS-Req-10.2.4
    - audit_rules_unsuccessful_file_modification_creat
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
Group   Record File Deletion Events by User   Group contains 5 rules

[ref]   At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

Rule   Ensure auditd Collects File Deletion Events by User - rmdir   [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_rmdir
Identifiers and References

References:  5.2.14, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000392-GPOS-00172, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S rmdir.*"
	GROUP="delete"
	FULL_RULE="-a always,exit -F arch=$ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit rmdir tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=delete$
    patterns: '*.rules'
  register: find_rmdir
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/delete.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/delete.rules
  when:
    - find_rmdir.matched is defined and find_rmdir.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_rmdir.files | map(attribute=''path'') | list | first }}'
  when:
    - find_rmdir.matched is defined and find_rmdir.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rmdir rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rmdir rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rmdir rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rmdir rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rmdir
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Ensure auditd Collects File Deletion Events by User - renameat   [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_renameat
Identifiers and References

References:  5.2.14, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000392-GPOS-00172, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S renameat.*"
	GROUP="delete"
	FULL_RULE="-a always,exit -F arch=$ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit renameat tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=delete$
    patterns: '*.rules'
  register: find_renameat
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/delete.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/delete.rules
  when:
    - find_renameat.matched is defined and find_renameat.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_renameat.files | map(attribute=''path'') | list | first }}'
  when:
    - find_renameat.matched is defined and find_renameat.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the renameat rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S renameat -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the renameat rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S renameat -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the renameat rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S renameat -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the renameat rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S renameat -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_renameat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Ensure auditd Collects File Deletion Events by User - rename   [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_rename
Identifiers and References

References:  5.2.14, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000392-GPOS-00172, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S rename.*"
	GROUP="delete"
	FULL_RULE="-a always,exit -F arch=$ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit rename tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=delete$
    patterns: '*.rules'
  register: find_rename
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/delete.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/delete.rules
  when:
    - find_rename.matched is defined and find_rename.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_rename.files | map(attribute=''path'') | list | first }}'
  when:
    - find_rename.matched is defined and find_rename.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rename rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S rename -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rename rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S rename -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rename rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S rename -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the rename rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S rename -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_rename
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Ensure auditd Collects File Deletion Events by User - unlinkat   [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_unlinkat
Identifiers and References

References:  5.2.14, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000392-GPOS-00172, SRG-OS-000466-VMM-001870, SRG-OS-000468-VMM-001890





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S unlinkat.*"
	GROUP="delete"
	FULL_RULE="-a always,exit -F arch=$ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit unlinkat tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=delete$
    patterns: '*.rules'
  register: find_unlinkat
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/delete.rules as
    the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/delete.rules
  when:
    - find_unlinkat.matched is defined and find_unlinkat.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_unlinkat.files | map(attribute=''path'') | list | first }}'
  when:
    - find_unlinkat.matched is defined and find_unlinkat.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the unlinkat rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the unlinkat rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the unlinkat rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the unlinkat rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_file_deletion_events_unlinkat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy
Group   Record Execution Attempts to Run SELinux Privileged Commands   Group contains 4 rules

[ref]   At a minimum, the audit system should collect the execution of SELinux privileged commands for all users and root.

Rule   Record Any Attempts to Run semanage   [ref]

At a minimum, the audit system should collect any execution attempt of the semanage command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_execution_semanage
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850





PATTERN="-a always,exit -F path=/usr/sbin/semanage\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/semanage.*$
    patterns: '*.rules'
  register: find_semanage
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_semanage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_semanage.matched is defined and find_semanage.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_semanage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_semanage.files | map(attribute=''path'') | list | first }}'
  when:
    - find_semanage.matched is defined and find_semanage.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_semanage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the semanage rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_semanage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the semanage rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_semanage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/semanage%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_semanage_execution.rules

Rule   Record Any Attempts to Run restorecon   [ref]

At a minimum, the audit system should collect any execution attempt of the restorecon command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_execution_restorecon
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850





PATTERN="-a always,exit -F path=/usr/sbin/restorecon\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/restorecon.*$
    patterns: '*.rules'
  register: find_restorecon
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_restorecon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_restorecon.matched is defined and find_restorecon.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_restorecon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_restorecon.files | map(attribute=''path'') | list | first }}'
  when:
    - find_restorecon.matched is defined and find_restorecon.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_restorecon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the restorecon rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_restorecon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the restorecon rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_restorecon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/restorecon%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_restorecon_execution.rules

Rule   Record Any Attempts to Run chcon   [ref]

At a minimum, the audit system should collect any execution attempt of the chcon command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_execution_chcon
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850





PATTERN="-a always,exit -F path=/usr/bin/chcon\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/chcon.*$
    patterns: '*.rules'
  register: find_chcon
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_chcon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_chcon.matched is defined and find_chcon.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_chcon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_chcon.files | map(attribute=''path'') | list | first }}'
  when:
    - find_chcon.matched is defined and find_chcon.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_chcon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the chcon rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_chcon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the chcon rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_chcon
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/chcon%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_chcon_execution.rules

Rule   Record Any Attempts to Run setsebool   [ref]

At a minimum, the audit system should collect any execution attempt of the setsebool command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged-priv_change

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_execution_setsebool
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000463-VMM-001850





PATTERN="-a always,exit -F path=/usr/sbin/setsebool\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/setsebool.*$
    patterns: '*.rules'
  register: find_setsebool
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_setsebool
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_setsebool.matched is defined and find_setsebool.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_setsebool
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_setsebool.files | map(attribute=''path'') | list | first }}'
  when:
    - find_setsebool.matched is defined and find_setsebool.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_setsebool
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the setsebool rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_setsebool
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the setsebool rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_execution_setsebool
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/setsebool%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_setsebool_execution.rules
Group   Record Attempts to Alter Logon and Logout Events   Group contains 3 rules
Group   Record Information on the Use of Privileged Commands   Group contains 16 rules

[ref]   At a minimum, the audit system should collect the execution of privileged commands for all users and root.

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - gpasswd   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_gpasswd
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/gpasswd\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/gpasswd.*$
    patterns: '*.rules'
  register: find_gpasswd
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_gpasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_gpasswd.matched is defined and find_gpasswd.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_gpasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_gpasswd.files | map(attribute=''path'') | list | first }}'
  when:
    - find_gpasswd.matched is defined and find_gpasswd.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_gpasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the gpasswd rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_gpasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the gpasswd rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_gpasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/gpasswd%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_gpasswd_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - postqueue   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_postqueue
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/sbin/postqueue\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/postqueue.*$
    patterns: '*.rules'
  register: find_postqueue
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postqueue
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_postqueue.matched is defined and find_postqueue.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postqueue
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_postqueue.files | map(attribute=''path'') | list | first }}'
  when:
    - find_postqueue.matched is defined and find_postqueue.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postqueue
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the postqueue rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postqueue
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the postqueue rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postqueue
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/postqueue%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_postqueue_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - newgrp   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_newgrp
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/newgrp\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/newgrp.*$
    patterns: '*.rules'
  register: find_newgrp
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_newgrp
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_newgrp.matched is defined and find_newgrp.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_newgrp
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_newgrp.files | map(attribute=''path'') | list | first }}'
  when:
    - find_newgrp.matched is defined and find_newgrp.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_newgrp
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the newgrp rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_newgrp
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the newgrp rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_newgrp
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/newgrp%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_newgrp_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - pam_timestamp_check   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_pam_timestamp_check
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/sbin/pam_timestamp_check\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/pam_timestamp_check.*$
    patterns: '*.rules'
  register: find_pam_timestamp_check
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_pam_timestamp_check
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_pam_timestamp_check.matched is defined and find_pam_timestamp_check.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_pam_timestamp_check
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_pam_timestamp_check.files | map(attribute=''path'') | list | first
        }}'
  when:
    - find_pam_timestamp_check.matched is defined and find_pam_timestamp_check.matched
      > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_pam_timestamp_check
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the pam_timestamp_check rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000
      -F auid!=unset -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_pam_timestamp_check
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the pam_timestamp_check rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000
      -F auid!=unset -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_pam_timestamp_check
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/pam_timestamp_check%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_pam_timestamp_check_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - sudoedit   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_sudoedit
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/sudoedit\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/sudoedit.*$
    patterns: '*.rules'
  register: find_sudoedit
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudoedit
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_sudoedit.matched is defined and find_sudoedit.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudoedit
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_sudoedit.files | map(attribute=''path'') | list | first }}'
  when:
    - find_sudoedit.matched is defined and find_sudoedit.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudoedit
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the sudoedit rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudoedit
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the sudoedit rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudoedit
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/sudoedit%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_sudoedit_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - userhelper   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_userhelper
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/sbin/userhelper\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/userhelper.*$
    patterns: '*.rules'
  register: find_userhelper
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_userhelper
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_userhelper.matched is defined and find_userhelper.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_userhelper
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_userhelper.files | map(attribute=''path'') | list | first }}'
  when:
    - find_userhelper.matched is defined and find_userhelper.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_userhelper
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the userhelper rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_userhelper
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the userhelper rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_userhelper
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/userhelper%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_userhelper_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - passwd   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_passwd
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/passwd\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/passwd.*$
    patterns: '*.rules'
  register: find_passwd
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_passwd.matched is defined and find_passwd.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_passwd.files | map(attribute=''path'') | list | first }}'
  when:
    - find_passwd.matched is defined and find_passwd.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the passwd rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the passwd rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/passwd%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_passwd_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - su   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_su
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/su\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/su.*$
    patterns: '*.rules'
  register: find_su
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_su
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_su.matched is defined and find_su.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_su
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_su.files | map(attribute=''path'') | list | first }}'
  when:
    - find_su.matched is defined and find_su.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_su
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the su rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_su
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the su rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_su
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/su%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_su_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - ssh-keysign   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/libexec/openssh/key-sign -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_ssh_keysign
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/libexec/openssh/ssh-keysign\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/libexec/openssh/ssh-keysign.*$
    patterns: '*.rules'
  register: find_ssh_keysign
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_ssh_keysign
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_ssh_keysign.matched is defined and find_ssh_keysign.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_ssh_keysign
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_ssh_keysign.files | map(attribute=''path'') | list | first }}'
  when:
    - find_ssh_keysign.matched is defined and find_ssh_keysign.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_ssh_keysign
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the ssh_keysign rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000
      -F auid!=unset -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_ssh_keysign
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the ssh_keysign rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000
      -F auid!=unset -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_ssh_keysign
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/libexec/openssh/ssh-keysign%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_libexec_openssh_ssh-keysign_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - chage   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_chage
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/chage\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/chage.*$
    patterns: '*.rules'
  register: find_chage
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_chage.matched is defined and find_chage.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_chage.files | map(attribute=''path'') | list | first }}'
  when:
    - find_chage.matched is defined and find_chage.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the chage rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the chage rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chage
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/chage%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_chage_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - unix_chkpwd   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_unix_chkpwd
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/sbin/unix_chkpwd\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/unix_chkpwd.*$
    patterns: '*.rules'
  register: find_unix_chkpwd
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_unix_chkpwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_unix_chkpwd.matched is defined and find_unix_chkpwd.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_unix_chkpwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_unix_chkpwd.files | map(attribute=''path'') | list | first }}'
  when:
    - find_unix_chkpwd.matched is defined and find_unix_chkpwd.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_unix_chkpwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the unix_chkpwd rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F
      auid!=unset -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_unix_chkpwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the unix_chkpwd rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F
      auid!=unset -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_unix_chkpwd
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/unix_chkpwd%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_unix_chkpwd_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - chsh   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_chsh
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/chsh\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/chsh.*$
    patterns: '*.rules'
  register: find_chsh
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chsh
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_chsh.matched is defined and find_chsh.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chsh
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_chsh.files | map(attribute=''path'') | list | first }}'
  when:
    - find_chsh.matched is defined and find_chsh.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chsh
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the chsh rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chsh
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the chsh rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_chsh
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/chsh%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_chsh_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - postdrop   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_postdrop
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/sbin/postdrop\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/sbin/postdrop.*$
    patterns: '*.rules'
  register: find_postdrop
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postdrop
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_postdrop.matched is defined and find_postdrop.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postdrop
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_postdrop.files | map(attribute=''path'') | list | first }}'
  when:
    - find_postdrop.matched is defined and find_postdrop.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postdrop
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the postdrop rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postdrop
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the postdrop rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_postdrop
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/sbin/postdrop%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_sbin_postdrop_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - umount   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_umount
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/umount\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/umount.*$
    patterns: '*.rules'
  register: find_umount
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_umount
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_umount.matched is defined and find_umount.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_umount
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_umount.files | map(attribute=''path'') | list | first }}'
  when:
    - find_umount.matched is defined and find_umount.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_umount
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the umount rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_umount
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the umount rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_umount
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/umount%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_umount_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - crontab   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_crontab
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/crontab\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/crontab.*$
    patterns: '*.rules'
  register: find_crontab
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_crontab
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_crontab.matched is defined and find_crontab.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_crontab
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_crontab.files | map(attribute=''path'') | list | first }}'
  when:
    - find_crontab.matched is defined and find_crontab.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_crontab
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the crontab rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_crontab
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the crontab rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_crontab
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/crontab%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_crontab_execution.rules

Rule   Ensure auditd Collects Information on the Use of Privileged Commands - sudo   [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=special-config-changes

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threast.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_sudo
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-VMM-001910





PATTERN="-a always,exit -F path=/usr/bin/sudo\\s\\+.*"
GROUP="privileged"
# Although the fix doesn't use ARCH, we reset it because it could have been set by some other remediation
ARCH=""
FULL_RULE="-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*path=/usr/bin/sudo.*$
    patterns: '*.rules'
  register: find_sudo
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudo
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/privileged.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_sudo.matched is defined and find_sudo.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudo
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_sudo.files | map(attribute=''path'') | list | first }}'
  when:
    - find_sudo.matched is defined and find_sudo.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudo
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the sudo rule in rules.d
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudo
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces the sudo rule in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset
      -F key=privileged
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - audit_rules_privileged_commands_sudo
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/sudo%20-F%20perm%3Dx%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_sudo_execution.rules
Group   Record Events that Modify the System's Discretionary Access Controls   Group contains 13 rules

[ref]   At a minimum, the audit system should collect file permission changes for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules:

-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rule   Record Events that Modify the System's Discretionary Access Controls - lsetxattr   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lsetxattr
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S lsetxattr.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit lsetxattr tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_lsetxattr
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_lsetxattr.matched is defined and find_lsetxattr.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_lsetxattr.files | map(attribute=''path'') | list | first }}'
  when:
    - find_lsetxattr.matched is defined and find_lsetxattr.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lsetxattr rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lsetxattr rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lsetxattr rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lsetxattr rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-lsetxattr_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - chmod   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chmod
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S chmod.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit chmod tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_chmod
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_chmod.matched is defined and find_chmod.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_chmod.files | map(attribute=''path'') | list | first }}'
  when:
    - find_chmod.matched is defined and find_chmod.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chmod rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chmod rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chmod rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chmod rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20chmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20chmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-chmod_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - chown   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chown
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S chown.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit chown tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_chown
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_chown.matched is defined and find_chown.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_chown.files | map(attribute=''path'') | list | first }}'
  when:
    - find_chown.matched is defined and find_chown.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chown rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chown rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chown rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the chown rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_chown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20chown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20chown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-chown_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - fchownat   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchownat
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S fchownat.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit fchownat tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_fchownat
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_fchownat.matched is defined and find_fchownat.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_fchownat.files | map(attribute=''path'') | list | first }}'
  when:
    - find_fchownat.matched is defined and find_fchownat.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchownat rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchownat rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchownat rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchownat rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchownat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchownat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchownat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-fchownat_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - fchmodat   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmodat
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S fchmodat.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit fchmodat tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_fchmodat
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_fchmodat.matched is defined and find_fchmodat.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_fchmodat.files | map(attribute=''path'') | list | first }}'
  when:
    - find_fchmodat.matched is defined and find_fchmodat.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmodat rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmodat rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmodat rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmodat rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmodat
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchmodat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchmodat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-fchmodat_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - fremovexattr   [ref]

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fremovexattr
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S fremovexattr.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit fremovexattr tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_fremovexattr
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_fremovexattr.matched is defined and find_fremovexattr.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_fremovexattr.files | map(attribute=''path'') | list | first }}'
  when:
    - find_fremovexattr.matched is defined and find_fremovexattr.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fremovexattr rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fremovexattr rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fremovexattr rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fremovexattr rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-fremovexattr_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - fchmod   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmod
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S fchmod.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit fchmod tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_fchmod
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_fchmod.matched is defined and find_fchmod.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_fchmod.files | map(attribute=''path'') | list | first }}'
  when:
    - find_fchmod.matched is defined and find_fchmod.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmod rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmod rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmod rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchmod rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchmod
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-fchmod_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - setxattr   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_setxattr
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S setxattr.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit setxattr tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_setxattr
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_setxattr.matched is defined and find_setxattr.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_setxattr.files | map(attribute=''path'') | list | first }}'
  when:
    - find_setxattr.matched is defined and find_setxattr.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the setxattr rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the setxattr rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the setxattr rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the setxattr rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_setxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20setxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20setxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-setxattr_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - removexattr   [ref]

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_removexattr
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S removexattr.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit removexattr tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_removexattr
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_removexattr.matched is defined and find_removexattr.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_removexattr.files | map(attribute=''path'') | list | first }}'
  when:
    - find_removexattr.matched is defined and find_removexattr.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the removexattr rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the removexattr rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the removexattr rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the removexattr rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_removexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20removexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20removexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-removexattr_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - lremovexattr   [ref]

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lremovexattr
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S lremovexattr.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit lremovexattr tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_lremovexattr
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_lremovexattr.matched is defined and find_lremovexattr.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_lremovexattr.files | map(attribute=''path'') | list | first }}'
  when:
    - find_lremovexattr.matched is defined and find_lremovexattr.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lremovexattr rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lremovexattr rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lremovexattr rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lremovexattr rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset
      -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lremovexattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-lremovexattr_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - fchown   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchown
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S fchown.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit fchown tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_fchown
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_fchown.matched is defined and find_fchown.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_fchown.files | map(attribute=''path'') | list | first }}'
  when:
    - find_fchown.matched is defined and find_fchown.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchown rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchown rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchown rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fchown rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-fchown_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - fsetxattr   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fsetxattr
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S fsetxattr.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit fsetxattr tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_fsetxattr
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_fsetxattr.matched is defined and find_fsetxattr.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_fsetxattr.files | map(attribute=''path'') | list | first }}'
  when:
    - find_fsetxattr.matched is defined and find_fsetxattr.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fsetxattr rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fsetxattr rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fsetxattr rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the fsetxattr rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F
      key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_fsetxattr
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-fsetxattr_dac_modification.rules

Rule   Record Events that Modify the System's Discretionary Access Controls - lchown   [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lchown
Identifiers and References

References:  5.2.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S lchown.*"
	GROUP="perm_mod"
	FULL_RULE="-a always,exit -F arch=$ARCH -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit lchown tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other DAC audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=perm_mod$
    patterns: '*.rules'
  register: find_lchown
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing DAC ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_lchown.matched is defined and find_lchown.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_lchown.files | map(attribute=''path'') | list | first }}'
  when:
    - find_lchown.matched is defined and find_lchown.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lchown rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lchown rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lchown rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the lchown rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_dac_modification_lchown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        filesystem: root
        mode: 0644
        path: /etc/audit/rules.d/75-lchown_dac_modification.rules
Group   Record Information on Kernel Modules Loading and Unloading   Group contains 2 rules

[ref]   To capture kernel module loading and unloading events, use following lines, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules
Place to add the lines depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the lines to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the lines to file /etc/audit/audit.rules.

Rule   Ensure auditd Collects Information on Kernel Module Loading - init_module   [ref]

To capture kernel module loading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.

Rationale:

The addition of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_init
Identifiers and References

References:  5.2.17, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SRG-OS-000477-VMM-001970





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
#       it's required on a 64-bit system to check also for the presence
#       of 32-bit's equivalent of the corresponding rule.
#       (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S init_module \(-F key=\|-k \).*"
	GROUP="modules"
	FULL_RULE="-a always,exit -F arch=$ARCH -S init_module -k modules"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

Rule   Ensure auditd Collects Information on Kernel Module Unloading - delete_module   [ref]

To capture kernel module unloading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S delete_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.

Rationale:

The removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_delete
Identifiers and References

References:  5.2.17, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SRG-OS-000477-VMM-001970





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
#       it's required on a 64-bit system to check also for the presence
#       of 32-bit's equivalent of the corresponding rule.
#       (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S delete_module \(-F key=\|-k \).*"
	GROUP="modules"
	FULL_RULE="-a always,exit -F arch=$ARCH -S delete_module -k modules"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done
Group   Records Events that Modify Date and Time Information   Group contains 5 rules

[ref]   Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All changes to the system time should be audited.

Rule   Record Attempts to Alter Time Through clock_settime   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_time_clock_settime
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S clock_settime -F a0=.* \(-F key=\|-k \).*"
	GROUP="clock_settime"
	FULL_RULE="-a always,exit -F arch=$ARCH -S clock_settime -F a0=0x0 -k time-change"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Strategy:restrict
- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_clock_settime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Perform remediation of Audit rules for clock_settime for x86 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - clock_settime

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(?:-F[\s]+a0=0x0[\s]+)(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b32_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b32_rules_d="{{ audit_syscalls_found_b32_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key time-change
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)time-change$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/time-change.rules as the recipient for the rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/time-change.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -F a0=0x0 -k time-change' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - clock_settime

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(?:-F[\s]+a0=0x0[\s]+)(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b32_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b32_audit_rules="{{ audit_syscalls_found_b32_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -F a0=0x0 -k time-change' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_audit_rules < audit_syscalls_number_of_syscalls
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_clock_settime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Perform remediation of Audit rules for clock_settime for x86_64 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - clock_settime

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(?:-F[\s]+a0=0x0[\s]+)(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b64_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b64_rules_d="{{ audit_syscalls_found_b64_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key time-change
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)time-change$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/time-change.rules as the recipient for the rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/time-change.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -F a0=0x0 -k time-change' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - clock_settime

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(?:-F[\s]+a0=0x0[\s]+)(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b64_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b64_audit_rules="{{ audit_syscalls_found_b64_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -F a0=0x0 -k time-change' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_audit_rules < audit_syscalls_number_of_syscalls
  when:
    - audit_arch == "b64"
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_clock_settime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Record Attempts to Alter Time Through stime   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d for both 32 bit and 64 bit systems:

-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_time_stime
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b



# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}


# Function to perform remediation for the 'adjtimex', 'settimeofday', and 'stime' audit
# system calls on RHEL, Fedora or OL systems.
# Remediation performed for both possible tools: 'auditctl' and 'augenrules'.
#
# Note: 'stime' system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore excluded from the list of time group system calls to be audited on this arch
#
# Example Call:
#
#      perform_audit_adjtimex_settimeofday_stime_remediation
#
function perform_audit_adjtimex_settimeofday_stime_remediation {

# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do

	PATTERN="-a always,exit -F arch=${ARCH} -S .* -k *"
	# Create expected audit group and audit rule form for particular system call & architecture
	if [ ${ARCH} = "b32" ]
	then
		# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
		# so append it to the list of time group system calls to be audited
		GROUP="\(adjtimex\|settimeofday\|stime\)"
		FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -S stime -k audit_time_rules"
	elif [ ${ARCH} = "b64" ]
	then
		# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
		# therefore don't add it to the list of time group system calls to be audited
		GROUP="\(adjtimex\|settimeofday\)"
		FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -k audit_time_rules"
	fi
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

}
perform_audit_adjtimex_settimeofday_stime_remediation


Complexity:low
Disruption:low
Strategy:restrict
- name: Perform remediation of Audit rules for stime syscall for x86 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - stime

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b32_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b32_rules_d="{{ audit_syscalls_found_b32_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_time_rules
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the
        rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_time_rules.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - stime

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b32_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b32_audit_rules="{{ audit_syscalls_found_b32_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_audit_rules < audit_syscalls_number_of_syscalls
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_stime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Record attempts to alter time through adjtimex   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_time_adjtimex
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b



# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}


# Function to perform remediation for the 'adjtimex', 'settimeofday', and 'stime' audit
# system calls on RHEL, Fedora or OL systems.
# Remediation performed for both possible tools: 'auditctl' and 'augenrules'.
#
# Note: 'stime' system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore excluded from the list of time group system calls to be audited on this arch
#
# Example Call:
#
#      perform_audit_adjtimex_settimeofday_stime_remediation
#
function perform_audit_adjtimex_settimeofday_stime_remediation {

# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do

	PATTERN="-a always,exit -F arch=${ARCH} -S .* -k *"
	# Create expected audit group and audit rule form for particular system call & architecture
	if [ ${ARCH} = "b32" ]
	then
		# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
		# so append it to the list of time group system calls to be audited
		GROUP="\(adjtimex\|settimeofday\|stime\)"
		FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -S stime -k audit_time_rules"
	elif [ ${ARCH} = "b64" ]
	then
		# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
		# therefore don't add it to the list of time group system calls to be audited
		GROUP="\(adjtimex\|settimeofday\)"
		FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -k audit_time_rules"
	fi
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

}
perform_audit_adjtimex_settimeofday_stime_remediation


Complexity:low
Disruption:low
Strategy:restrict
- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_adjtimex
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Perform remediation of Audit rules for adjtimex for x86 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - adjtimex

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b32_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b32_rules_d="{{ audit_syscalls_found_b32_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_time_rules
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the
        rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_time_rules.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - adjtimex

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b32_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b32_audit_rules="{{ audit_syscalls_found_b32_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_audit_rules < audit_syscalls_number_of_syscalls
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_adjtimex
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Perform remediation of Audit rules for adjtimex for x86_64 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - adjtimex

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b64_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b64_rules_d="{{ audit_syscalls_found_b64_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_time_rules
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the
        rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_time_rules.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - adjtimex

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b64_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b64_audit_rules="{{ audit_syscalls_found_b64_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_audit_rules < audit_syscalls_number_of_syscalls
  when:
    - audit_arch == "b64"
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_adjtimex
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Record attempts to alter time through settimeofday   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_time_settimeofday
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b



# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}


# Function to perform remediation for the 'adjtimex', 'settimeofday', and 'stime' audit
# system calls on RHEL, Fedora or OL systems.
# Remediation performed for both possible tools: 'auditctl' and 'augenrules'.
#
# Note: 'stime' system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore excluded from the list of time group system calls to be audited on this arch
#
# Example Call:
#
#      perform_audit_adjtimex_settimeofday_stime_remediation
#
function perform_audit_adjtimex_settimeofday_stime_remediation {

# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do

	PATTERN="-a always,exit -F arch=${ARCH} -S .* -k *"
	# Create expected audit group and audit rule form for particular system call & architecture
	if [ ${ARCH} = "b32" ]
	then
		# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
		# so append it to the list of time group system calls to be audited
		GROUP="\(adjtimex\|settimeofday\|stime\)"
		FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -S stime -k audit_time_rules"
	elif [ ${ARCH} = "b64" ]
	then
		# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
		# therefore don't add it to the list of time group system calls to be audited
		GROUP="\(adjtimex\|settimeofday\)"
		FULL_RULE="-a always,exit -F arch=${ARCH} -S adjtimex -S settimeofday -k audit_time_rules"
	fi
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

}
perform_audit_adjtimex_settimeofday_stime_remediation


Complexity:low
Disruption:low
Strategy:restrict
- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_settimeofday
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Perform remediation of Audit rules for settimeofday for x86 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - settimeofday

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b32_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b32_rules_d="{{ audit_syscalls_found_b32_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_time_rules
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the
        rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_time_rules.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - settimeofday

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b32_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b32_audit_rules="{{ audit_syscalls_found_b32_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_audit_rules < audit_syscalls_number_of_syscalls
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_settimeofday
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Perform remediation of Audit rules for settimeofday for x86_64 platform
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - settimeofday

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b64_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b64_rules_d="{{ audit_syscalls_found_b64_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_time_rules
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the
        rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_time_rules.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - settimeofday

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b64_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b64_audit_rules="{{ audit_syscalls_found_b64_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_time_rules' }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_audit_rules < audit_syscalls_number_of_syscalls
  when:
    - audit_arch == "b64"
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_settimeofday
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Record Attempts to Alter the localtime File   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_time_watch_localtime
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
fix_audit_watch_rule "augenrules" "/etc/localtime" "wa" "audit_time_rules"


Complexity:low
Disruption:low
Strategy:restrict
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_time_rules
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/audit_time_rules.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/localtime in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/localtime -p wa -k audit_time_rules
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/localtime already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/localtime in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/localtime -p wa -k audit_time_rules
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.4.2.b
    - audit_rules_time_watch_localtime
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Record Events that Modify the System's Network Environment   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

Rationale:

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_networkconfig_modification
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.5.5





# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S .* -k *"
	# Use escaped BRE regex to specify rule group
	GROUP="set\(host\|domain\)name"
	FULL_RULE="-a always,exit -F arch=$ARCH -S sethostname -S setdomainname -k audit_rules_networkconfig_modification"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done

# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/issue" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/issue" "wa" "audit_rules_networkconfig_modification"
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/issue.net" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/issue.net" "wa" "audit_rules_networkconfig_modification"
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/hosts" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/hosts" "wa" "audit_rules_networkconfig_modification"
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/sysconfig/network" "wa" "audit_rules_networkconfig_modification"
fix_audit_watch_rule "augenrules" "/etc/sysconfig/network" "wa" "audit_rules_networkconfig_modification"


Complexity:low
Disruption:low
Strategy:restrict
- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Remediate audit rules for network configuration for x86
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - sethostname
          - setdomainname

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b32_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b32_rules_d="{{ audit_syscalls_found_b32_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_rules_networkconfig_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as
        the recipient for the rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_rules_networkconfig_modification'
            }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - sethostname
          - setdomainname

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b32 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b32[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b32_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b32 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b32_audit_rules="{{ audit_syscalls_found_b32_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b32"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b32_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_rules_networkconfig_modification'
            }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b32_audit_rules < audit_syscalls_number_of_syscalls
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Remediate audit rules for network configuration for x86_64
  block:

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - sethostname
          - setdomainname

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: '*.rules'
      register: audit_syscalls_found_b64_rules_d
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/rules.d/
      set_fact: audit_syscalls_matched_b64_rules_d="{{ audit_syscalls_found_b64_rules_d.results|sum(attribute='matched')|int
        }}"

    - name: Search /etc/audit/rules.d for other rules with the key audit_rules_networkconfig_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
        patterns: '*.rules'
      register: find_syscalls_files

    - name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as
        the recipient for the rule
      set_fact:
        all_files:
          - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        == 0

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
          - '{{ find_syscalls_files.files | map(attribute=''path'') | list | first
            }}'
      when: find_syscalls_files.matched is defined and find_syscalls_files.matched
        > 0

    - name: Insert the syscall rule in {{ all_files[0] }}
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_rules_d.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_rules_networkconfig_modification'
            }}"

        - name: Insert the line in {{ all_files[0] }}
          lineinfile:
            path: '{{ all_files[0] }}'
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_rules_d < audit_syscalls_number_of_syscalls

    - name: Declare list of syscals
      set_fact:
        syscalls:
          - sethostname
          - setdomainname

    - name: Declare number of syscalls
      set_fact: audit_syscalls_number_of_syscalls="{{ syscalls|length|int }}"

    - name: Check existence of syscalls for architecture b64 in /etc/audit/audit.rules
      find:
        paths: /etc/audit
        contains: ^[\s]*-a[\s]+always,exit[\s]+(?:.*-F[\s]+arch=b64[\s]+)(?:.*(-S[\s]+{{
          item }}[\s]+|([\s]+|[,]){{ item }}([\s]+|[,]))).*(-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
        patterns: audit.rules
      register: audit_syscalls_found_b64_audit_rules
      loop: '{{ syscalls }}'

    - name: Get number of matched syscalls for architecture b64 in /etc/audit/audit.rules
      set_fact: audit_syscalls_matched_b64_audit_rules="{{ audit_syscalls_found_b64_audit_rules.results|sum(attribute='matched')|int
        }}"

    - name: Insert the syscall rule in /etc/audit/audit.rules
      block:

        - name: 'Construct rule: add rule list, action and arch'
          set_fact: tmpline="-a always,exit -F arch=b64"

        - name: 'Construct rule: add syscalls'
          set_fact: tmpline="{{ tmpline + ' -S ' + item.item }}"
          loop: '{{ audit_syscalls_found_b64_audit_rules.results }}'
          when: item.matched is defined and item.matched == 0

        - name: 'Construct rule: add fields and key'
          set_fact: tmpline="{{ tmpline + ' -k audit_rules_networkconfig_modification'
            }}"

        - name: Insert the line in /etc/audit/audit.rules
          lineinfile:
            path: /etc/audit/audit.rules
            line: '{{ tmpline }}'
            create: true
            state: present
      when: audit_syscalls_matched_b64_audit_rules < audit_syscalls_number_of_syscalls
  when:
    - audit_arch == "b64"
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/issue already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/issue in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/issue already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/issue in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/issue.net in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/issue.net in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/hosts already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/hosts in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/hosts already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/hosts in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/sysconfig/network in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Add watch rule for /etc/sysconfig/network in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_networkconfig_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Make the auditd Configuration Immutable   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d in order to make the auditd configuration immutable:

-e 2
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file in order to make the auditd configuration immutable:
-e 2
With this setting, a reboot will be required to change any audit rules.

Rationale:

Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_immutable
Identifiers and References

References:  4.1.18, 1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.4.3, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.310(a)(2)(iv), 164.312(d), 164.310(d)(2)(iii), 164.312(b), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5.2




# Traverse all of:
#
# /etc/audit/audit.rules,			(for auditctl case)
# /etc/audit/rules.d/*.rules			(for augenrules case)
#
# files to check if '-e .*' setting is present in that '*.rules' file already.
# If found, delete such occurrence since auditctl(8) manual page instructs the
# '-e 2' rule should be placed as the last rule in the configuration
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-e[[:space:]]\+.*/d' {} ';'

# Append '-e 2' requirement at the end of both:
# * /etc/audit/audit.rules file 		(for auditctl case)
# * /etc/audit/rules.d/immutable.rules		(for augenrules case)

for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
	echo '' >> $AUDIT_FILE
	echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_FILE
	echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_FILE
	echo '-e 2' >> $AUDIT_FILE
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Collect all files from /etc/audit/rules.d with .rules extension
  find:
    paths: /etc/audit/rules.d/
    patterns: '*.rules'
  register: find_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-171-3.4.3
    - NIST-800-53-AC-6(9)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.2
    - audit_rules_immutable
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Remove the -e option from all Audit config files
  lineinfile:
    path: '{{ item }}'
    regexp: ^\s*(?:-e)\s+.*$
    state: absent
  loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
    }}'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-171-3.4.3
    - NIST-800-53-AC-6(9)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.2
    - audit_rules_immutable
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add Audit -e option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
  lineinfile:
    path: '{{ item }}'
    create: true
    line: -e 2
  loop:
    - /etc/audit/audit.rules
    - /etc/audit/rules.d/immutable.rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-171-3.4.3
    - NIST-800-53-AC-6(9)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.2
    - audit_rules_immutable
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Attempts to Alter Process and Session Initiation Information   [ref]

The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing such process information:

-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for attempted manual edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session

Rationale:

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_session_events
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3





# Perform the remediation
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/var/run/utmp" "wa" "session"
fix_audit_watch_rule "augenrules" "/var/run/utmp" "wa" "session"
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/var/log/btmp" "wa" "session"
fix_audit_watch_rule "augenrules" "/var/log/btmp" "wa" "session"
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/var/log/wtmp" "wa" "session"
fix_audit_watch_rule "augenrules" "/var/log/wtmp" "wa" "session"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key session
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)session$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/session.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /var/run/utmp in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/run/utmp -p wa -k session
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /var/run/utmp in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/run/utmp -p wa -k session
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key session
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)session$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/session.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/log/btmp -p wa -k session
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/log/btmp -p wa -k session
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key session
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)session$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/session.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/log/wtmp -p wa -k session
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/log/wtmp -p wa -k session
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.3
    - audit_rules_session_events
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Events that Modify User/Group Information - /etc/shadow   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/shadow -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/shadow -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_shadow
Identifiers and References

References:  5.2.5, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/shadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/shadow" "wa" "audit_rules_usergroup_modification"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit shadow tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_shadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other user/group modification audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -k audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_shadow
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_shadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_shadow.matched is defined and find_shadow.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_shadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_shadow.files | map(attribute=''path'') | list | first }}'
  when:
    - find_shadow.matched is defined and find_shadow.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_shadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the shadow rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_shadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the shadow rule in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_shadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Events that Modify User/Group Information - /etc/gshadow   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/gshadow -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/gshadow -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_gshadow
Identifiers and References

References:  5.2.5, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit gshadow tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_gshadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other user/group modification audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -k audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_gshadow
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_gshadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_gshadow.matched is defined and find_gshadow.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_gshadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_gshadow.files | map(attribute=''path'') | list | first }}'
  when:
    - find_gshadow.matched is defined and find_gshadow.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_gshadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the gshadow rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_gshadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the gshadow rule in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_gshadow
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Events that Modify User/Group Information - /etc/security/opasswd   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_opasswd
Identifiers and References

References:  5.2.5, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000003-GPOS-00004, SRG-OS-000004-GPOS-00004, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit opasswd tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_opasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other user/group modification audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -k audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_opasswd
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_opasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_opasswd.matched is defined and find_opasswd.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_opasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_opasswd.files | map(attribute=''path'') | list | first }}'
  when:
    - find_opasswd.matched is defined and find_opasswd.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_opasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the opasswd rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_opasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the opasswd rule in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_opasswd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Events that Modify User/Group Information - /etc/group   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_group
Identifiers and References

References:  5.2.5, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/group" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/group" "wa" "audit_rules_usergroup_modification"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit group tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_group
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other user/group modification audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -k audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_group
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_group
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_group.matched is defined and find_group.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_group
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_group.files | map(attribute=''path'') | list | first }}'
  when:
    - find_group.matched is defined and find_group.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_group
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the group rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/group -p wa -k audit_rules_usergroup_modification
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_group
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the group rule in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/group -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_group
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Events that Modify the System's Mandatory Access Controls   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policy

Rationale:

The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_mac_modification
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.8, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/selinux/" "wa" "MAC-policy"
fix_audit_watch_rule "augenrules" "/etc/selinux/" "wa" "MAC-policy"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key MAC-policy
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)MAC-policy$
    patterns: '*.rules'
  register: find_watch_key
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use /etc/audit/rules.d/MAC-policy.rules as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/MAC-policy.rules
  when:
    - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
    - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
      is defined and find_existing_watch_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /etc/selinux/ in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/selinux/ -p wa -k MAC-policy
    create: true
  when:
    - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add watch rule for /etc/selinux/ in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/selinux/ -p wa -k MAC-policy
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.8
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.5.5
    - audit_rules_mac_modification
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Shutdown System When Auditing Failures Occur   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-f 2
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to the top of the /etc/audit/audit.rules file:
-f 2

Rationale:

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected.

Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_system_shutdown
Identifiers and References

References:  1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 3.3.1, 3.3.4, CCI-000139, CCI-000140, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, AU-5(b), SC-24, CM-6(a), PR.PT-1, SRG-OS-000046-GPOS-00022, SRG-OS-000047-GPOS-00023, SRG-OS-000047-VMM-000220




# Traverse all of:
#
# /etc/audit/audit.rules,			(for auditctl case)
# /etc/audit/rules.d/*.rules			(for augenrules case)
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-f[[:space:]]\+.*/d' {} ';'

for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
	echo '' >> $AUDIT_FILE
	echo '# Set the audit.rules configuration to halt system upon audit failure per security requirements' >> $AUDIT_FILE
	echo '-f 2' >> $AUDIT_FILE
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Collect all files from /etc/audit/rules.d with .rules extension
  find:
    paths: /etc/audit/rules.d/
    patterns: '*.rules'
  register: find_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.3.1
    - NIST-800-171-3.3.4
    - NIST-800-53-AU-5(b)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-24
    - audit_rules_system_shutdown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Remove the -f option from all Audit config files
  lineinfile:
    path: '{{ item }}'
    regexp: ^\s*(?:-f)\s+.*$
    state: absent
  loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
    }}'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.3.1
    - NIST-800-171-3.3.4
    - NIST-800-53-AU-5(b)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-24
    - audit_rules_system_shutdown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Add Audit -f option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
  lineinfile:
    path: '{{ item }}'
    create: true
    line: -f 2
  loop:
    - /etc/audit/audit.rules
    - /etc/audit/rules.d/immutable.rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.3.1
    - NIST-800-171-3.3.4
    - NIST-800-53-AU-5(b)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-24
    - audit_rules_system_shutdown
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Record Events that Modify User/Group Information - /etc/passwd   [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/passwd -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/passwd -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_passwd
Identifiers and References

References:  5.2.5, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107, SRG-OS-000303-GPOS-00120, SRG-OS-000476-GPOS-00221, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/passwd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/passwd" "wa" "audit_rules_usergroup_modification"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit passwd tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other user/group modification audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -k audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_passwd
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/privileged.rules
  when:
    - find_passwd.matched is defined and find_passwd.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_passwd.files | map(attribute=''path'') | list | first }}'
  when:
    - find_passwd.matched is defined and find_passwd.matched > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the passwd rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the passwd rule in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(4)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.5
    - audit_rules_usergroup_modification_passwd
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Ensure auditd Collects Information on Exporting to Media (successful)   [ref]

At a minimum, the audit system should collect media exportation events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export

Rationale:

The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_media_export
Identifiers and References

References:  5.2.13, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.7, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172





# Perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	PATTERN="-a always,exit -F arch=$ARCH -S .* -F auid>=1000 -F auid!=unset -k *"
	GROUP="mount"
	FULL_RULE="-a always,exit -F arch=$ARCH -S mount -F auid>=1000 -F auid!=unset -k export"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix syscall audit rule for given system call. It is
# based on example audit syscall rule definitions as outlined in
# /usr/share/doc/audit-2.3.7/stig.rules file provided with the audit
# package. It will combine multiple system calls belonging to the same
# syscall group into one audit rule (rather than to create audit rule per
# different system call) to avoid audit infrastructure performance penalty
# in the case of 'one-audit-rule-definition-per-one-system-call'. See:
#
#   https://www.redhat.com/archives/linux-audit/2014-November/msg00009.html
#
# for further details.
#
# Expects five arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules
# * audit rules' pattern		audit rule skeleton for same syscall
# * syscall group			greatest common string this rule shares
# 					with other rules from the same group
# * architecture			architecture this rule is intended for
# * full form of new rule to add	expected full form of audit rule as to be
# 					added into audit.rules file
#
# Note: The 2-th up to 4-th arguments are used to determine how many existing
# audit rules will be inspected for resemblance with the new audit rule
# (5-th argument) the function is going to add. The rule's similarity check
# is performed to optimize audit.rules definition (merge syscalls of the same
# group into one rule) to avoid the "single-syscall-per-audit-rule" performance
# penalty.
#
# Example call:
#
#	See e.g. 'audit_rules_file_deletion_events.sh' remediation script
#
function fix_audit_syscall_rule {

# Load function arguments into local variables
local tool="$1"
local pattern="$2"
local group="$3"
local arch="$4"
local full_rule="$5"

# Check sanity of the input
if [ $# -ne "5" ]
then
	echo "Usage: fix_audit_syscall_rule 'tool' 'pattern' 'group' 'arch' 'full rule'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
# 
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
declare -a files_to_inspect

retval=0

# First check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	return 1
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules' )
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
elif [ "$tool" == 'augenrules' ]
then
	# Extract audit $key from audit rule so we can use it later
	matches=()
	key=$(expr "$full_rule" : '.*-k[[:space:]]\([^[:space:]]\+\)' '|' "$full_rule" : '.*-F[[:space:]]key=\([^[:space:]]\+\)')
	readarray -t matches < <(sed -s -n -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d;F" /etc/audit/rules.d/*.rules)
	if [ $? -ne 0 ]
	then
		retval=1
	fi
	for match in "${matches[@]}"
	do
		files_to_inspect+=("${match}")
	done
	# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
	if [ ${#files_to_inspect[@]} -eq "0" ]
	then
		file_to_inspect="/etc/audit/rules.d/$key.rules"
		files_to_inspect=("$file_to_inspect")
		if [ ! -e "$file_to_inspect" ]
		then
			touch "$file_to_inspect"
			chmod 0640 "$file_to_inspect"
		fi
	fi
fi

#
# Indicator that we want to append $full_rule into $audit_file by default
local append_expected_rule=0

for audit_file in "${files_to_inspect[@]}"
do
	# Filter existing $audit_file rules' definitions to select those that:
	# * follow the rule pattern, and
	# * meet the hardware architecture requirement, and
	# * are current syscall group specific
	readarray -t existing_rules < <(sed -e "\;${pattern};!d" -e "/${arch}/!d" -e "/${group}/!d"  "$audit_file")
	if [ $? -ne 0 ]
	then
		retval=1
	fi

	# Process rules found case-by-case
	for rule in "${existing_rules[@]}"
	do
		# Found rule is for same arch & key, but differs (e.g. in count of -S arguments)
		if [ "${rule}" != "${full_rule}" ]
		then
			# If so, isolate just '(-S \w)+' substring of that rule
			rule_syscalls=$(echo "$rule" | grep -o -P '(-S \w+ )+')
			# Check if list of '-S syscall' arguments of that rule is subset
			# of '-S syscall' list of expected $full_rule
			if grep -q -- "$rule_syscalls" <<< "$full_rule"
			then
				# Rule is covered (i.e. the list of -S syscalls for this rule is
				# subset of -S syscalls of $full_rule => existing rule can be deleted
				# Thus delete the rule from audit.rules & our array
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi
				existing_rules=("${existing_rules[@]//$rule/}")
			else
				# Rule isn't covered by $full_rule - it besides -S syscall arguments
				# for this group contains also -S syscall arguments for other syscall
				# group. Example: '-S lchown -S fchmod -S fchownat' => group='chown'
				# since 'lchown' & 'fchownat' share 'chown' substring
				# Therefore:
				# * 1) delete the original rule from audit.rules
				# (original '-S lchown -S fchmod -S fchownat' rule would be deleted)
				# * 2) delete the -S syscall arguments for this syscall group, but
				# keep those not belonging to this syscall group
				# (original '-S lchown -S fchmod -S fchownat' would become '-S fchmod'
				# * 3) append the modified (filtered) rule again into audit.rules
				# if the same rule not already present
				#
				# 1) Delete the original rule
				sed -i -e "\;${rule};d" "$audit_file"
				if [ $? -ne 0 ]
				then
					retval=1
				fi

				# 2) Delete syscalls for this group, but keep those from other groups
				# Convert current rule syscall's string into array splitting by '-S' delimiter
				IFS_BKP="$IFS"
				IFS=$'-S'
				read -a rule_syscalls_as_array <<< "$rule_syscalls"
				# Reset IFS back to default
				IFS="$IFS_BKP"
				# Splitting by "-S" can't be replaced by the readarray functionality easily

				# Declare new empty string to hold '-S syscall' arguments from other groups
				new_syscalls_for_rule=''
				# Walk through existing '-S syscall' arguments
				for syscall_arg in "${rule_syscalls_as_array[@]}"
				do
					# Skip empty $syscall_arg values
					if [ "$syscall_arg" == '' ]
					then
						continue
					fi
					# If the '-S syscall' doesn't belong to current group add it to the new list
					# (together with adding '-S' delimiter back for each of such item found)
					if grep -q -v -- "$group" <<< "$syscall_arg"
					then
						new_syscalls_for_rule="$new_syscalls_for_rule -S $syscall_arg"
					fi
				done
				# Replace original '-S syscall' list with the new one for this rule
				updated_rule=${rule//$rule_syscalls/$new_syscalls_for_rule}
				# Squeeze repeated whitespace characters in rule definition (if any) into one
				updated_rule=$(echo "$updated_rule" | tr -s '[:space:]')
				# 3) Append the modified / filtered rule again into audit.rules
				#    (but only in case it's not present yet to prevent duplicate definitions)
				if ! grep -q -- "$updated_rule" "$audit_file"
				then
					echo "$updated_rule" >> "$audit_file"
				fi
			fi
		else
			# $audit_file already contains the expected rule form for this
			# architecture & key => don't insert it second time
			append_expected_rule=1
		fi
	done

	# We deleted all rules that were subset of the expected one for this arch & key.
	# Also isolated rules containing system calls not from this system calls group.
	# Now append the expected rule if it's not present in $audit_file yet
	if [[ ${append_expected_rule} -eq "0" ]]
	then
		echo "$full_rule" >> "$audit_file"
	fi
done

return $retval

}
	fix_audit_syscall_rule "auditctl" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
	fix_audit_syscall_rule "augenrules" "$PATTERN" "$GROUP" "$ARCH" "$FULL_RULE"
done


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: Set architecture for audit media export tasks
  set_fact:
    audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if the rule for x86_64 is already present in /etc/audit/rules.d/*
  find:
    paths: /etc/audit/rules.d/
    contains: ^\s*-a\s+always,exit\s+-F\s+arch=b64\s+-S\s+mount\s+-F\s+auid>=1000\s+-F\s+auid!=unset(\s|$)+
    patterns: '*.rules'
  register: find_existing_media_export_64_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if the rule for x86 is already present in /etc/audit/rules.d/*
  find:
    paths: /etc/audit/rules.d/
    contains: ^\s*-a\s+always,exit\s+-F\s+arch=b32\s+-S\s+mount\s+-F\s+auid>=1000\s+-F\s+auid!=unset(\s|$)+
    patterns: '*.rules'
  register: find_existing_media_export_32_rules_d
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if the rule for x86_64 is already present in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-a\s+always,exit\s+-F\s+arch=b64\s+-S\s+mount\s+-F\s+auid>=1000\s+-F\s+auid!=unset(\s|$)+
    patterns: audit.rules
  register: find_existing_media_export_64_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Check if the rule for x86 is already present in /etc/audit/rules.d/*
  find:
    paths: /etc/audit/
    contains: ^\s*-a\s+always,exit\s+-F\s+arch=b32\s+-S\s+mount\s+-F\s+auid>=1000\s+-F\s+auid!=unset(\s|$)+
    patterns: audit.rules
  register: find_existing_media_export_32_audit_rules
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Search /etc/audit/rules.d for other media export audit rules
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: -F key=export$
    patterns: '*.rules'
  register: find_mount
  when:
    - (find_existing_media_export_32_rules_d is defined and find_existing_media_export_32_rules_d.matched
      == 0) or (find_existing_media_export_64_rules_d is defined and find_existing_media_export_64_rules_d.matched
      == 0)
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: If existing media export ruleset not found, use /etc/audit/rules.d/export.rules
    as the recipient for the rule
  set_fact:
    all_files:
      - /etc/audit/rules.d/export.rules
  when:
    - find_mount.matched is defined and find_mount.matched == 0 and ((find_existing_media_export_32_rules_d
      is defined and find_existing_media_export_32_rules_d.matched == 0) or (find_existing_media_export_64_rules_d
      is defined and find_existing_media_export_64_rules_d.matched == 0))
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
      - '{{ find_mount.files | map(attribute=''path'') | list | first }}'
  when:
    - find_mount.matched is defined and find_mount.matched > 0 and ((find_existing_media_export_32_rules_d
      is defined and find_existing_media_export_32_rules_d.matched == 0) or (find_existing_media_export_64_rules_d
      is defined and find_existing_media_export_64_rules_d.matched == 0))
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the media export rule in rules.d when on x86
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b32 -S mount -F auid>=1000 -F auid!=unset -F key=export
    create: true
  when:
    - find_existing_media_export_32_rules_d is defined and find_existing_media_export_32_rules_d.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the media export rule in rules.d when on x86_64
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -a always,exit -F arch=b64 -S mount -F auid>=1000 -F auid!=unset -F key=export
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64' and find_existing_media_export_64_rules_d
      is defined and find_existing_media_export_64_rules_d.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the media export rule in /etc/audit/audit.rules when on x86
  lineinfile:
    line: -a always,exit -F arch=b32 -S mount -F auid>=1000 -F auid!=unset -F key=export
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - find_existing_media_export_32_audit_rules is defined and find_existing_media_export_32_audit_rules.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Inserts/replaces the media export rule in audit.rules when on x86_64
  lineinfile:
    line: -a always,exit -F arch=b64 -S mount -F auid>=1000 -F auid!=unset -F key=export
    state: present
    dest: /etc/audit/audit.rules
    create: true
  when:
    - audit_arch is defined and audit_arch == 'b64' and find_existing_media_export_64_audit_rules
      is defined and find_existing_media_export_64_audit_rules.matched == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.7
    - audit_rules_media_export
    - low_complexity
    - low_disruption
    - medium_severity
    - reboot_required
    - restrict_strategy

Rule   Ensure auditd Collects System Administrator Actions   [ref]

At a minimum, the audit system should collect administrator actions for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions

Rationale:

The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_audit_rules_sysadmin_actions
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(7)(b), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000462-VMM-001840, SRG-OS-000471-VMM-001910





# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/sudoers" "wa" "actions"
fix_audit_watch_rule "augenrules" "/etc/sudoers" "wa" "actions"
# Function to fix audit file system object watch rule for given path:
# * if rule exists, also verifies the -w bits match the requirements
# * if rule doesn't exist yet, appends expected rule form to $files_to_inspect
#   audit rules file, depending on the tool which was used to load audit rules
#
# Expects four arguments (each of them is required) in the form of:
# * audit tool				tool used to load audit rules,
# 					either 'auditctl', or 'augenrules'
# * path                        	value of -w audit rule's argument
# * required access bits        	value of -p audit rule's argument
# * key                         	value of -k audit rule's argument
#
# Example call:
#
#       fix_audit_watch_rule "auditctl" "/etc/localtime" "wa" "audit_time_rules"
#
function fix_audit_watch_rule {

# Load function arguments into local variables
local tool="$1"
local path="$2"
local required_access_bits="$3"
local key="$4"

# Check sanity of the input
if [ $# -ne "4" ]
then
	echo "Usage: fix_audit_watch_rule 'tool' 'path' 'bits' 'key'"
	echo "Aborting."
	exit 1
fi

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
declare -a files_to_inspect
files_to_inspect=()

# Check sanity of the specified audit tool
if [ "$tool" != 'auditctl' ] && [ "$tool" != 'augenrules' ]
then
	echo "Unknown audit rules loading tool: $1. Aborting."
	echo "Use either 'auditctl' or 'augenrules'!"
	exit 1
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
elif [ "$tool" == 'auditctl' ]
then
	files_to_inspect+=('/etc/audit/audit.rules')
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/$key.rules' to list of files for inspection.
elif [ "$tool" == 'augenrules' ]
then
	readarray -t matches < <(grep -P "[\s]*-w[\s]+$path" /etc/audit/rules.d/*.rules)

	# For each of the matched entries
	for match in "${matches[@]}"
	do
		# Extract filepath from the match
		rulesd_audit_file=$(echo $match | cut -f1 -d ':')
		# Append that path into list of files for inspection
		files_to_inspect+=("$rulesd_audit_file")
	done
	# Case when particular audit rule isn't defined yet
	if [ "${#files_to_inspect[@]}" -eq "0" ]
	then
		# Append '/etc/audit/rules.d/$key.rules' into list of files for inspection
		local key_rule_file="/etc/audit/rules.d/$key.rules"
		# If the $key.rules file doesn't exist yet, create it with correct permissions
		if [ ! -e "$key_rule_file" ]
		then
			touch "$key_rule_file"
			chmod 0640 "$key_rule_file"
		fi

		files_to_inspect+=("$key_rule_file")
	fi
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do

	# Check if audit watch file system object rule for given path already present
	if grep -q -P -- "[\s]*-w[\s]+$path" "$audit_rules_file"
	then
		# Rule is found => verify yet if existing rule definition contains
		# all of the required access type bits

		# Escape slashes in path for use in sed pattern below
		local esc_path=${path//$'/'/$'\/'}
		# Define BRE whitespace class shortcut
		local sp="[[:space:]]"
		# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
		current_access_bits=$(sed -ne "s/$sp*-w$sp\+$esc_path$sp\+-p$sp\+\([rxwa]\{1,4\}\).*/\1/p" "$audit_rules_file")
		# Split required access bits string into characters array
		# (to check bit's presence for one bit at a time)
		for access_bit in $(echo "$required_access_bits" | grep -o .)
		do
			# For each from the required access bits (e.g. 'w', 'a') check
			# if they are already present in current access bits for rule.
			# If not, append that bit at the end
			if ! grep -q "$access_bit" <<< "$current_access_bits"
			then
				# Concatenate the existing mask with the missing bit
				current_access_bits="$current_access_bits$access_bit"
			fi
		done
		# Propagate the updated rule's access bits (original + the required
		# ones) back into the /etc/audit/audit.rules file for that rule
		sed -i "s/\($sp*-w$sp\+$esc_path$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)/\1$current_access_bits\3/" "$audit_rules_file"
	else
		# Rule isn't present yet. Append it at the end of $audit_rules_file file
		# with proper key

		echo "-w $path -p $required_access_bits -k $key" >> "$audit_rules_file"
	fi
done
}
fix_audit_watch_rule "auditctl" "/etc/sudoers.d/" "wa" "actions"
fix_audit_watch_rule "augenrules" "/etc/sudoers.d/" "wa" "actions"


Complexity:low
Disruption:low
Strategy:restrict
- name: Search /etc/audit/rules.d for audit rule entries for sysadmin actions
  find:
    paths: /etc/audit/rules.d
    recurse: false
    contains: ^.*/etc/sudoers.*$
    patterns: '*.rules'
  register: find_audit_sysadmin_actions
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
  set_fact:
    all_sysadmin_actions_files:
      - /etc/audit/rules.d/actions.rules
  when:
    - find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
      == 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_sysadmin_actions_files:
      - '{{ find_audit_sysadmin_actions.files | map(attribute=''path'') | list | first
        }}'
  when:
    - find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
      > 0
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces audit rule for /etc/sudoers rule in rules.d
  lineinfile:
    path: '{{ all_sysadmin_actions_files[0] }}'
    line: -w /etc/sudoers -p wa -k actions
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces audit rule for /etc/sudoers.d rule in rules.d
  lineinfile:
    path: '{{ all_sysadmin_actions_files[0] }}'
    line: -w /etc/sudoers.d/ -p wa -k actions
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces audit rule for /etc/sudoers in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -w /etc/sudoers -p wa -k actions
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Inserts/replaces audit rule for /etc/sudoers.d in audit.rules
  lineinfile:
    path: /etc/audit/audit.rules
    line: -w /etc/sudoers.d/ -p wa -k actions
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.1.7
    - NIST-800-53-AC-2(7)(b)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.2.2
    - PCI-DSS-Req-10.2.5.b
    - audit_rules_sysadmin_actions
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Enable auditd Service   [ref]

The auditd service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The auditd service can be enabled with the following command:

$ sudo systemctl enable auditd.service

Rationale:

Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the auditd service is active ensures audit records generated by the kernel are appropriately recorded.

Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_service_auditd_enabled
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-001464, CCI-001487, CCI-001814, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.1, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000042-GPOS-00021, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000365-GPOS-00152, SRG-OS-000037-VMM-000150, SRG-OS-000063-VMM-000310, SRG-OS-000038-VMM-000160, SRG-OS-000039-VMM-000170, SRG-OS-000040-VMM-000180, SRG-OS-000041-VMM-000190



Complexity:low
Disruption:low
Strategy:enable

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" start 'auditd.service'
"$SYSTEMCTL_EXEC" enable 'auditd.service'


Complexity:low
Disruption:low
Strategy:enable
- name: Enable service auditd
  block:

    - name: Gather the package facts
      package_facts:
        manager: auto

    - name: Enable service auditd
      service:
        name: auditd
        enabled: 'yes'
        state: started
      when:
        - '"audit" in ansible_facts.packages'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-171-3.3.2
    - NIST-800-171-3.3.6
    - NIST-800-53-AC-2(g)
    - NIST-800-53-AC-6(9)
    - NIST-800-53-AU-10
    - NIST-800-53-AU-12(c)
    - NIST-800-53-AU-14(1)
    - NIST-800-53-AU-2(d)
    - NIST-800-53-AU-3
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-10.1
    - enable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_auditd_enabled


Complexity:low
Disruption:low
Strategy:enable
include enable_auditd

class enable_auditd {
  service {'auditd':
    enable => true,
    ensure => 'running',
  }
}


apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    systemd:
      units:
      - name: auditd.service
        enabled: true

Rule   Enable Auditing for Processes Which Start Prior to the Audit Daemon   [ref]

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument audit=1 to the default GRUB 2 command line for the Linux operating system in /boot/grub2/grubenv, in the manner below:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit=1"

Warning:  The GRUB 2 configuration file, grub.cfg, is automatically updated each time a new kernel is installed. Note that any changes to /etc/default/grub require rebuilding the grub.cfg file. To update the GRUB 2 configuration file manually, use the
grub2-mkconfig -o
command as follows:
  • On BIOS-based machines, issue the following command as root:
    ~]# grub2-mkconfig -o /boot/grub2/grub.cfg
  • On UEFI-based machines, issue the following command as root:
    ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
Rationale:

Each process on the system carries an "auditable" flag which indicates whether its activities can be audited. Although auditd takes care of enabling this for all processes which launch after it does, adding the kernel argument ensures it is set for every process during boot.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_grub2_audit_argument
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.02, DSS05.03, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001464, CCI-000130, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AC-17(1), AU-14(1), AU-10, CM-6(a), IR-5(1), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.3, SRG-OS-000254-GPOS-00095, SRG-OS-000254-VMM-000880





# Correct grub2 kernelopts value using grub2-editenv
if ! grub2-editenv - list | grep -qE '^kernelopts=(.*\s)?audit=1(\s.*)?$'; then
  grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit=1"
fi


Complexity:medium
Disruption:low
Reboot:true
Strategy:restrict
- name: get current kernel parameters
  command: /usr/bin/grub2-editenv - list
  register: kernelopts
  changed_when: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-53-AC-17(1)
    - NIST-800-53-AU-10
    - NIST-800-53-AU-14(1)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IR-5(1)
    - PCI-DSS-Req-10.3
    - grub2_audit_argument
    - low_disruption
    - medium_complexity
    - medium_severity
    - reboot_required
    - restrict_strategy

- name: Update the bootloader menu
  command: /usr/bin/grub2-editenv - set "{{ item }} audit=1"
  with_items: '{{ kernelopts.stdout_lines | select(''match'', ''^kernelopts.*'') |
    list }}'
  when:
    - kernelopts.stdout_lines is defined
    - kernelopts.stdout_lines | length > 0
    - kernelopts.stdout | regex_search('^kernelopts=(?:.*\s)?audit=1(?:\s.*)?$', multiline=True)
      is none
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.4.1.1
    - NIST-800-171-3.3.1
    - NIST-800-53-AC-17(1)
    - NIST-800-53-AU-10
    - NIST-800-53-AU-14(1)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IR-5(1)
    - PCI-DSS-Req-10.3
    - grub2_audit_argument
    - low_disruption
    - medium_complexity
    - medium_severity
    - reboot_required
    - restrict_strategy
Group   Installing and Maintaining Software   Group contains 8 groups and 12 rules

[ref]   The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.

Group   Updating Software   Group contains 4 rules

[ref]   The yum command line tool is used to install and update software packages. The system also provides a graphical software update tool in the System menu, in the Administration submenu, called Software Update.

Oracle Linux 8 systems contain an installed software catalog called the RPM database, which records metadata of installed packages. Consistently using yum or the graphical Software Update for all software installation allows for insight into the current inventory of installed software on the system.

Rule   Ensure gpgcheck Enabled for Local Packages   [ref]

yum should be configured to verify the signature(s) of local packages prior to installation. To configure yum to verify signatures of local packages, set the localpkg_gpgcheck to 1 in /etc/yum.conf.

Rationale:

Changes to any software components can have significant effects to the overall security of the operating system. This requirement ensures the software has not been tampered and has been provided by a trusted vendor.

Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_ensure_gpgcheck_local_packages
Identifiers and References

References:  NT28(R15), 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-11(a), CM-11(b), CM-6(a), CM-5(3), SA-12, SA-12(10), PR.IP-1, FAU_GEN.1.1.c, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650



# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/yum.conf' '^localpkg_gpgcheck' '1' ''


Complexity:low
Disruption:medium
- name: Check existence of yum on Fedora
  stat:
    path: /etc/yum.conf
  register: yum_config_file
  check_mode: false
  when: ansible_distribution == "Fedora"
  tags:
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - ensure_gpgcheck_local_packages
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed
    - unknown_strategy

- name: Ensure GPG check Enabled for Local Packages (Yum)
  ini_file:
    dest: /etc/yum.conf
    section: main
    option: localpkg_gpgcheck
    value: 1
    create: true
  when: (ansible_distribution == "RedHat" or ansible_distribution == "CentOS" or ansible_distribution
    == "Scientific" or yum_config_file.stat.exists)
  tags:
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - ensure_gpgcheck_local_packages
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed
    - unknown_strategy

- name: Ensure GPG check Enabled for Local Packages (DNF)
  ini_file:
    dest: /etc/dnf/dnf.conf
    section: main
    option: localpkg_gpgcheck
    value: 1
    create: true
  when: ansible_distribution == "Fedora"
  tags:
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - ensure_gpgcheck_local_packages
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed
    - unknown_strategy

Rule   Ensure Oracle Linux GPG Key Installed   [ref]

To ensure the system can cryptographically verify base software packages come from Oracle (and to connect to the Unbreakable Linux Network to receive them), the Oracle GPG key must properly be installed. To install the Oracle GPG key, run:

$ sudo uln_register
If the system is not connected to the Internet, then install the Oracle GPG key from trusted media such as the Oracle installation CD-ROM or DVD. Assuming the disc is mounted in /media/cdrom, use the following command as the root user to import it into the keyring:
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY

Rationale:

Changes to software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. The Oracle GPG key is necessary to cryptographically verify packages are from Oracle.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_ensure_oracle_gpgkey_installed
Identifiers and References

References:  1.2.2, 11, 2, 3, 9, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, CCI-001749, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, Req-6.2



# OL fingerprints below retrieved from Oracle Linux Yum Server "Frequently Asked Questions"
# https://yum.oracle.com/faq.html#a10
readonly OL_FINGERPRINT="42144123FECFC55B9086313D72F97B74EC551F03"
readonly OL8_FINGERPRINT="76FD3DB13AB67410B89DB10E82562EA9AD986DA3"

# Location of the key we would like to import (once it's integrity verified)
readonly OL_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-oracle"

RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$OL_RELEASE_KEY")")

# Verify /etc/pki/rpm-gpg directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
  # If they are safe, try to obtain fingerprints from the key file
  # (to ensure there won't be e.g. CRC error)
  readarray -t GPG_OUT < <(gpg --with-fingerprint --with-colons "$OL_RELEASE_KEY" | grep "^fpr" | cut -d ":" -f 10)
  GPG_RESULT=$?
  # No CRC error, safe to proceed
  if [ "${GPG_RESULT}" -eq "0" ]
  then
    # Filter just hexadecimal fingerprints from gpg's output from
    # processing of a key file
    echo "${GPG_OUT[*]}" | grep -vE "${OL_FINGERPRINT}|${OL8_FINGERPRINT}" || {
      # If $ OL_RELEASE_KEY file doesn't contain any keys with unknown fingerprint, import it
      rpm --import "${OL_RELEASE_KEY}"
    }
  fi
fi

Rule   Ensure gpgcheck Enabled for All yum Package Repositories   [ref]

To ensure signature checking is not disabled for any repos, remove any lines from files in /etc/yum.repos.d of the form:

gpgcheck=0

Rationale:

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA)."

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_ensure_gpgcheck_never_disabled
Identifiers and References

References:  NT28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FAU_GEN.1.1.c, Req-6.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650



sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/yum.repos.d/*


Complexity:low
Disruption:medium
Strategy:enable
- name: Grep for yum repo section names
  shell: grep -HEr '^\[.+\]' -r /etc/yum.repos.d/
  register: repo_grep_results
  ignore_errors: true
  changed_when: false
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - NIST-800-53-SC-12
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SI-7
    - PCI-DSS-Req-6.2
    - enable_strategy
    - ensure_gpgcheck_never_disabled
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed

- name: Set gpgcheck=1 for each yum repo
  ini_file:
    path: '{{ item[0] }}'
    section: '{{ item[1] }}'
    option: gpgcheck
    value: '1'
    no_extra_spaces: true
  loop: '{{ repo_grep_results.stdout | regex_findall( ''(.+\.repo):\[(.+)\]\n?'' )
    }}'
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - NIST-800-53-SC-12
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SI-7
    - PCI-DSS-Req-6.2
    - enable_strategy
    - ensure_gpgcheck_never_disabled
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed

Rule   Ensure gpgcheck Enabled In Main yum Configuration   [ref]

The gpgcheck option controls whether RPM packages' signatures are always checked prior to installation. To configure yum to check package signatures before installing them, ensure the following line appears in /etc/yum.conf in the [main] section:

gpgcheck=1

Rationale:

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.
Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA).

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_ensure_gpgcheck_globally_activated
Identifiers and References

References:  NT28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FAU_GEN.1.1.c, Req-6.2, SRG-OS-000366-GPOS-00153, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650



# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append "/etc/yum.conf" '^gpgcheck' '1' ''


Complexity:low
Disruption:medium
- name: Check existence of yum on Fedora
  stat:
    path: /etc/yum.conf
  register: yum_config_file
  check_mode: false
  when: ansible_distribution == "Fedora"
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - NIST-800-53-SC-12
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SI-7
    - PCI-DSS-Req-6.2
    - ensure_gpgcheck_globally_activated
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed
    - unknown_strategy

- name: Ensure GPG check is globally activated (yum)
  ini_file:
    dest: /etc/yum.conf
    section: main
    option: gpgcheck
    value: 1
    no_extra_spaces: true
    create: false
  when: (ansible_distribution == "RedHat" or ansible_distribution == "CentOS" or ansible_distribution
    == "Scientific" or yum_config_file.stat.exists)
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - NIST-800-53-SC-12
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SI-7
    - PCI-DSS-Req-6.2
    - ensure_gpgcheck_globally_activated
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed
    - unknown_strategy

- name: Ensure GPG check is globally activated (dnf)
  ini_file:
    dest: /etc/dnf/dnf.conf
    section: main
    option: gpgcheck
    value: 1
    no_extra_spaces: true
    create: false
  when: ansible_distribution == "Fedora"
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.4.8
    - NIST-800-53-CM-11(a)
    - NIST-800-53-CM-11(b)
    - NIST-800-53-CM-5(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SA-12
    - NIST-800-53-SA-12(10)
    - NIST-800-53-SC-12
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SI-7
    - PCI-DSS-Req-6.2
    - ensure_gpgcheck_globally_activated
    - high_severity
    - low_complexity
    - medium_disruption
    - no_reboot_needed
    - unknown_strategy
Group   System and Software Integrity   Group contains 3 groups and 4 rules

[ref]   System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software, enabling SELinux, installing an Intrusion Prevention System, etc. However, installing or enabling integrity checking tools cannot prevent intrusions, but they can detect that an intrusion may have occurred. Requirements for integrity checking may be highly dependent on the environment in which the system will be used. Snapshot-based approaches such as AIDE may induce considerable overhead in the presence of frequent software updates.

Group   Software Integrity Checking   Group contains 1 group and 2 rules

[ref]   Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integrity of installed software. AIDE uses snapshots of file metadata (such as hashes) and compares these to current system files in order to detect changes.

The RPM package management system can conduct integrity checks by comparing information in its metadata database with files installed on the system.

Group   Verify Integrity with RPM   Group contains 2 rules

[ref]   The RPM package management system includes the ability to verify the integrity of installed packages by comparing the installed files with information about the files taken from the package metadata stored in the RPM database. Although an attacker could corrupt the RPM database (analogous to attacking the AIDE database as described above), this check can still reveal modification of important files. To list which files on the system differ from what is expected by the RPM database:

$ rpm -qVa
See the man page for rpm to see a complete explanation of each column.

Rule   Verify File Hashes with RPM   [ref]

Without cryptographic integrity protections, system executables and files can be altered by unauthorized users without detection. The RPM package management system can check the hashes of installed software packages, including many that are important to system security. To verify that the cryptographic hash of system files and commands match vendor values, run the following command to list which files on the system have hashes that differ from what is expected by the RPM database:

$ rpm -Va | grep '^..5'
A "c" in the second column indicates that a file is a configuration file, which may appropriately be expected to change. If the file was not expected to change, investigate the cause of the change using audit logs or other means. The package can then be reinstalled to restore the file. Run the following command to determine which package owns the file:
$ rpm -qf FILENAME
The package can be reinstalled from a yum repository using the command:
$ sudo yum reinstall PACKAGENAME
Alternatively, the package can be reinstalled from trusted media using the command:
$ sudo rpm -Uvh PACKAGENAME

Rationale:

The hashes of important files like system executables should match the information given by the RPM database. Executables with erroneous hashes could be a sign of nefarious activity on the system.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_rpm_verify_hashes
Identifiers and References

References:  1.2.6, 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.3.8, 3.4.1, CCI-000366, CCI-000663, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), PR.DS-6, PR.DS-8, PR.IP-1, Req-11.5, SRG-OS-000480-GPOS-00227




# Find which files have incorrect hash (not in /etc, because there are all system related config. files) and then get files names
files_with_incorrect_hash="$(rpm -Va | grep -E '^..5.* /(bin|sbin|lib|lib64|usr)/' | awk '{print $NF}' )"
# From files names get package names and change newline to space, because rpm writes each package to new line
packages_to_reinstall="$(rpm -qf $files_with_incorrect_hash | tr '\n' ' ')"

yum reinstall -y $packages_to_reinstall


Complexity:high
Disruption:medium
Strategy:restrict
- name: 'Set fact: Package manager reinstall command (dnf)'
  set_fact:
    package_manager_reinstall_cmd: dnf reinstall -y
  when: ansible_distribution == "Fedora"
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_hashes

- name: 'Set fact: Package manager reinstall command (yum)'
  set_fact:
    package_manager_reinstall_cmd: yum reinstall -y
  when: (ansible_distribution == "RedHat" or ansible_distribution == "OracleLinux")
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_hashes

- name: Read files with incorrect hash
  command: rpm -Va --nodeps --nosize --nomtime --nordev --nocaps --nolinkto --nouser
    --nogroup --nomode --noconfig --noghost
  args:
    warn: false
  register: files_with_incorrect_hash
  changed_when: false
  failed_when: files_with_incorrect_hash.rc > 1
  check_mode: false
  when: (package_manager_reinstall_cmd is defined)
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_hashes

- name: Create list of packages
  command: rpm -qf "{{ item }}"
  args:
    warn: false
  with_items: '{{ files_with_incorrect_hash.stdout_lines | map(''regex_findall'',
    ''^[.]+[5]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
    | list | unique }}'
  register: list_of_packages
  changed_when: false
  check_mode: false
  when:
    - files_with_incorrect_hash.stdout_lines is defined
    - (files_with_incorrect_hash.stdout_lines | length > 0)
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_hashes

- name: Reinstall packages of files with incorrect hash
  command: '{{ package_manager_reinstall_cmd }} ''{{ item }}'''
  args:
    warn: false
  with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
    | unique }}'
  when:
    - files_with_incorrect_hash.stdout_lines is defined
    - (package_manager_reinstall_cmd is defined and (files_with_incorrect_hash.stdout_lines
      | length > 0))
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_hashes

Rule   Verify and Correct File Permissions with RPM   [ref]

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. Verify that the file permissions of system files and commands match vendor values. Check the file permissions with the following command:

$ sudo rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'
Output indicates files that do not match vendor defaults. After locating a file with incorrect permissions, run the following command to determine which package owns it:
$ rpm -qf FILENAME

Next, run the following command to reset its permissions to the correct values:
$ sudo rpm --setperms PACKAGENAME

Warning:  Profiles may require that specific files have stricter file permissions than defined by the vendor. Such files will be reported as a finding and need to be evaluated according to your policy and deployment environment.
Rationale:

Permissions on system binaries and configuration files that are too generous could allow an unauthorized user to gain privileges that they should not have. The permissions set by the vendor should be maintained. Any deviations from this baseline should be investigated.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_rpm_verify_permissions
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, 5.10.4.1, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.8, 3.4.1, CCI-001493, CCI-001494, CCI-001495, CCI-001496, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), CM-6(a), PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, Req-11.5, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000278-GPOS-00108



Complexity:high
Disruption:medium
Strategy:restrict

# Declare array to hold set of RPM packages we need to correct permissions for
declare -A SETPERMS_RPM_DICT

# Create a list of files on the system having permissions different from what
# is expected by the RPM database
readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,2,1)=="M") print $NF }')

for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
	RPM_PACKAGE=$(rpm -qf "$FILE_PATH")
	# Use an associative array to store packages as it's keys, not having to care about duplicates.
	SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
done

# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
do
	rpm --setperms "${RPM_PACKAGE}"
done


Complexity:high
Disruption:medium
Strategy:restrict
- name: Read list of files with incorrect permissions
  command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
    --nocaps --nolinkto --nouser --nogroup
  args:
    warn: false
  register: files_with_incorrect_permissions
  failed_when: files_with_incorrect_permissions.rc > 1
  changed_when: false
  check_mode: false
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_permissions

- name: Create list of packages
  command: rpm -qf "{{ item }}"
  args:
    warn: false
  with_items: '{{ files_with_incorrect_permissions.stdout_lines | map(''regex_findall'',
    ''^[.]+[M]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
    | list | unique }}'
  register: list_of_packages
  changed_when: false
  check_mode: false
  when: (files_with_incorrect_permissions.stdout_lines | length > 0)
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_permissions

- name: Correct file permissions with RPM
  command: rpm --setperms '{{ item }}'
  args:
    warn: false
  with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
    | unique }}'
  when: (files_with_incorrect_permissions.stdout_lines | length > 0)
  tags:
    - CJIS-5.10.4.1
    - NIST-800-171-3.3.8
    - NIST-800-171-3.4.1
    - NIST-800-53-AU-9(3)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-6(c)
    - NIST-800-53-CM-6(d)
    - NIST-800-53-SI-7
    - NIST-800-53-SI-7(1)
    - NIST-800-53-SI-7(6)
    - PCI-DSS-Req-11.5
    - high_complexity
    - high_severity
    - medium_disruption
    - no_reboot_needed
    - restrict_strategy
    - rpm_verify_permissions
Group   System Cryptographic Policies   Group contains 2 rules

[ref]   Linux has the capability to centrally configure cryptographic polices. The command update-crypto-policies is used to set the policy applicable for the various cryptographic back-ends, such as SSL/TLS libraries. The configured cryptographic policies will be the default policy used by these backends unless the application user configures them otherwise. When the system has been configured to use the centralized cryptographic policies, the administrator is assured that any application that utilizes the supported backends will follow a policy that adheres to the configured profile. Currently the supported backends are:

  • GnuTLS library
  • OpenSSL library
  • NSS library
  • OpenJDK
  • Libkrb5
  • BIND
  • OpenSSH
Applications and languages which rely on any of these backends will follow the system policies as well. Examples are apache httpd, nginx, php, and others.

Rule   Configure SSH to use System Crypto Policy   [ref]

Crypto Policies provide a centralized control over crypto algorithms usage of many packages. SSH is supported by crypto policy, but the SSH configuration may be set up to ignore it. To check that Crypto Policies settings are configured correctly, ensure that the CRYPTO_POLICY variable is either commented or not set at all in the /etc/sysconfig/sshd.

Rationale:

Overriding the system crypto policy makes the behavior of the SSH service violate expectations, and makes system configuration more fragmented.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_configure_ssh_crypto_policy
Identifiers and References

References:  AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13




SSH_CONF="/etc/sysconfig/sshd"

sed -i "/^\s*CRYPTO_POLICY.*$/d" $SSH_CONF


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
- name: Configure SSH to use System Crypto Policy
  lineinfile:
    dest: /etc/sysconfig/sshd
    state: absent
    regexp: ^\s*CRYPTO_POLICY.*$
  tags:
    - NIST-800-53-AC-17(2)
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-MA-4(6)
    - NIST-800-53-SC-13
    - configure_ssh_crypto_policy
    - disable_strategy
    - low_complexity
    - medium_disruption
    - medium_severity
    - reboot_required

Rule   Configure System Cryptography Policy   [ref]

To configure the system cryptography policy to use ciphers only from the FIPS policy, run the following command:

$ sudo update-crypto-policies --set FIPS
The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied. Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon.

Warning:  The system needs to be rebooted for these changes to take effect.
Warning:  System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.
Rationale:

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_configure_crypto_policy
Identifiers and References

References:  AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3), SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174




var_system_crypto_policy="FIPS"

stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?

if test "$rc" = 127; then
	echo "$stderr_of_call" >&2
	echo "Make sure that the script is installed on the remediated system." >&2
	echo "See output of the 'dnf provides update-crypto-policies' command" >&2
	echo "to see what package to (re)install" >&2

	false  # end with an error code
elif test "$rc" != 0; then
	echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
	false  # end with an error code
fi


Complexity:low
Disruption:low
Strategy:restrict
- name: XCCDF Value var_system_crypto_policy # promote to variable
  set_fact:
    var_system_crypto_policy: !!str FIPS
  tags:
    - always

- name: Configure System Cryptography Policy
  lineinfile:
    path: /etc/crypto-policies/config
    regexp: ^(?!#)(\S+)$
    line: '{{ var_system_crypto_policy }}'
    create: true
  tags:
    - NIST-800-53-AC-17(2)
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-MA-4(6)
    - NIST-800-53-SC-12(2)
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SC-13
    - configure_crypto_policy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - restrict_strategy

- name: Verify that Crypto Policy is Set (runtime)
  command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy }}
  tags:
    - NIST-800-53-AC-17(2)
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-MA-4(6)
    - NIST-800-53-SC-12(2)
    - NIST-800-53-SC-12(3)
    - NIST-800-53-SC-13
    - configure_crypto_policy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - restrict_strategy
Group   GNOME Desktop Environment   Group contains 1 group and 3 rules

[ref]   GNOME is a graphical desktop environment bundled with many Linux distributions that allow users to easily interact with the operating system graphically rather than textually. The GNOME Graphical Display Manager (GDM) provides login, logout, and user switching contexts as well as display server management.

GNOME is developed by the GNOME Project and is considered the default Oracle Linux Graphical environment.

For more information on GNOME and the GNOME Project, see https://www.gnome.org.

Group   GNOME Remote Access Settings   Group contains 2 rules

[ref]   GNOME remote access settings that apply to the graphical interface.

Rule   Require Credential Prompting for Remote Access in GNOME3   [ref]

By default, GNOME does not require credentials when using Vino for remote access. To configure the system to require remote credentials, add or set authentication-methods to ['vnc'] in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/Vino]
authentication-methods=['vnc']
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/Vino/authentication-methods
After the settings have been set, run dconf update.

Rationale:

Username and password prompting is required for remote access. Otherwise, non-authorized and nefarious users can access the system freely.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_credential_prompt
Identifiers and References

References:  3.1.12, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)





# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/Vino\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
    [ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
    printf '%s\n' "[org/gnome/Vino]" >> ${DCONFFILE}
    printf '%s=%s\n' "authentication-methods" "['vnc']" >> ${DCONFFILE}
else
    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "['vnc']")"
    if grep -q "^\\s*authentication-methods" "${SETTINGSFILES[@]}"
    then
        sed -i "s/\\s*authentication-methods\\s*=\\s*.*/authentication-methods=${escaped_value}/g" "${SETTINGSFILES[@]}"
    else
        sed -i "\\|\\[org/gnome/Vino\\]|a\\authentication-methods=${escaped_value}" "${SETTINGSFILES[@]}"
    fi
fi

dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/Vino/authentication-methods$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"

mkdir -p "${LOCKSFOLDER}"

if [[ -z "${LOCKFILES}" ]]
then
    echo "/org/gnome/Vino/authentication-methods" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi

dconf update


Complexity:low
Disruption:medium
- name: Require Credential Prompting for Remote Access in GNOME3
  ini_file:
    dest: /etc/dconf/db/local.d/00-security-settings
    section: org/gnome/Vino
    option: authentication-methods
    value: '[''vnc'']'
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - dconf_gnome_remote_access_credential_prompt
    - low_complexity
    - medium_disruption
    - medium_severity
    - no_reboot_needed
    - unknown_strategy

- name: Prevent user modification of GNOME3 Credential Prompting for Remote Access
  lineinfile:
    path: /etc/dconf/db/local.d/locks/00-security-settings-lock
    regexp: ^/org/gnome/Vino/authentication-methods
    line: /org/gnome/Vino/authentication-methods
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - dconf_gnome_remote_access_credential_prompt
    - low_complexity
    - medium_disruption
    - medium_severity
    - no_reboot_needed
    - unknown_strategy

Rule   Require Encryption for Remote Access in GNOME3   [ref]

By default, GNOME requires encryption when using Vino for remote access. To prevent remote access encryption from being disabled, add or set require-encryption to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/Vino]
require-encryption=true
Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:
/org/gnome/Vino/require-encryption
After the settings have been set, run dconf update.

Rationale:

Open X displays allow an attacker to capture keystrokes and to execute commands remotely.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_encryption
Identifiers and References

References:  1, 11, 12, 13, 15, 16, 18, 20, 3, 4, 6, 9, BAI03.08, BAI07.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS03.01, 3.1.13, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 7.6, A.12.1.1, A.12.1.2, A.12.1.4, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(a), AC-17(a), AC-17(2), DE.AE-1, PR.DS-7, PR.IP-1, SRG-OS-000480-GPOS-00227





# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/Vino\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
    [ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
    printf '%s\n' "[org/gnome/Vino]" >> ${DCONFFILE}
    printf '%s=%s\n' "require-encryption" "true" >> ${DCONFFILE}
else
    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*require-encryption" "${SETTINGSFILES[@]}"
    then
        sed -i "s/\\s*require-encryption\\s*=\\s*.*/require-encryption=${escaped_value}/g" "${SETTINGSFILES[@]}"
    else
        sed -i "\\|\\[org/gnome/Vino\\]|a\\require-encryption=${escaped_value}" "${SETTINGSFILES[@]}"
    fi
fi

dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/Vino/require-encryption$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"

mkdir -p "${LOCKSFOLDER}"

if [[ -z "${LOCKFILES}" ]]
then
    echo "/org/gnome/Vino/require-encryption" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi

dconf update


Complexity:low
Disruption:medium
- name: Require Encryption for Remote Access in GNOME3
  ini_file:
    dest: /etc/dconf/db/local.d/00-security-settings
    section: org/gnome/Vino
    option: require-encryption
    value: 'true'
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-53-AC-17(2)
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - dconf_gnome_remote_access_encryption
    - low_complexity
    - medium_disruption
    - medium_severity
    - no_reboot_needed
    - unknown_strategy

- name: Prevent user modification of GNOME3 Encryption for Remote Access
  lineinfile:
    path: /etc/dconf/db/local.d/locks/00-security-settings-lock
    regexp: ^/org/gnome/Vino/require-encryption
    line: /org/gnome/Vino/require-encryption
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-53-AC-17(2)
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - dconf_gnome_remote_access_encryption
    - low_complexity
    - medium_disruption
    - medium_severity
    - no_reboot_needed
    - unknown_strategy

Rule   Make sure that the dconf databases are up-to-date with regards to respective keyfiles   [ref]

By default, DConf uses a binary database as a data backend. The system-level database is compiled from keyfiles in the /etc/dconf/db/ directory by the

dconf update
command.

Rationale:

Unlike text-based keyfiles, the binary database is impossible to check by OVAL. Therefore, in order to evaluate dconf configuration, both have to be true at the same time - configuration files have to be compliant, and the database needs to be more recent than those keyfiles, which gives confidence that it reflects them.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_dconf_db_up_to_date
Identifiers and References

References:  SRG-OS-000480-GPOS-00227

Group   Disk Partitioning   Group contains 1 rule

[ref]   To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logical volume. The installer's default partitioning scheme creates separate logical volumes for /, /boot, and swap.

  • If starting with any of the default layouts, check the box to \"Review and modify partitioning.\" This allows for the easy creation of additional logical volumes inside the volume group already created, though it may require making /'s logical volume smaller to create space. In general, using logical volumes is preferable to using partitions because they can be more easily adjusted later.
  • If creating a custom layout, create the partitions mentioned in the previous paragraph (which the installer will require anyway), as well as separate ones described in the following sections.
If a system has already been installed, and the default partitioning scheme was used, it is possible but nontrivial to modify it to create separate logical volumes for the directories listed above. The Logical Volume Manager (LVM) makes this possible. See the LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/ for more detailed information on LVM.

Rule   Encrypt Partitions   [ref]

Oracle Linux 8 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time.

For manual installations, select the Encrypt checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots.

For automated/unattended installations, it is possible to use Kickstart by adding the --encrypted and --passphrase= options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition:

part / --fstype=ext4 --size=100 --onpart=hda1 --encrypted --passphrase=PASSPHRASE
Any PASSPHRASE is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the --passphrase= option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation.

By default, the Anaconda installer uses aes-xts-plain64 cipher with a minimum 512 bit key size which should be compatible with FIPS enabled.

Detailed information on encrypting partitions using LUKS or LUKS ciphers can be found on the Oracle Linux 8 Documentation web site:
https://docs.oracle.com/cd/E52668_01/E54670/html/ol7-encrypt-sec.html.

Rationale:

The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_encrypt_partitions
Identifiers and References

References:  13, 14, APO01.06, BAI02.01, BAI06.01, DSS04.07, DSS05.03, DSS05.04, DSS05.07, DSS06.02, DSS06.06, 3.13.16, CCI-001199, CCI-002475, CCI-002476, 164.308(a)(1)(ii)(D), 164.308(b)(1), 164.310(d), 164.312(a)(1), 164.312(a)(2)(iii), 164.312(a)(2)(iv), 164.312(b), 164.312(c), 164.314(b)(2)(i), 164.312(d), SR 3.4, SR 4.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), SC-28, SC-28(1), SC-13, AU-9(3), PR.DS-1, PR.DS-5, SRG-OS-000405-GPOS-00184, SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183, SRG-OS-000404-VMM-001650, SRG-OS-000405-VMM-001660

Group   GRUB2 bootloader configuration   Group contains 8 rules

[ref]   During the boot process, the boot loader is responsible for starting the execution of the kernel and passing options to it. The boot loader allows for the selection of different kernels - possibly on different partitions or media. The default Oracle Linux 8 boot loader for x86 systems is called GRUB2. Options it can pass to the kernel include single-user mode, which provides root access without any authentication, and the ability to disable SELinux. To prevent local users from modifying the boot parameters and endangering security, protect the boot loader configuration with a password and ensure its configuration file's permissions are set properly.

Rule   Verify /boot/grub2/grub.cfg Group Ownership   [ref]

The file /boot/grub2/grub.cfg should be group-owned by the root group to prevent destruction or modification of the file. To properly set the group owner of /boot/grub2/grub.cfg, run the command:

$ sudo chgrp root /boot/grub2/grub.cfg

Rationale:

The root group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_file_groupowner_grub2_cfg
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1



Complexity:low
Disruption:low
Strategy:configure


chgrp 0 /boot/grub2/grub.cfg


Complexity:low
Disruption:low
Strategy:configure
- name: Test for existence /boot/grub2/grub.cfg
  stat:
    path: /boot/grub2/grub.cfg
  register: file_exists
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_groupowner_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

- name: Ensure group owner 0 on /boot/grub2/grub.cfg
  file:
    path: /boot/grub2/grub.cfg
    group: '0'
  when:
    - file_exists.stat is defined and file_exists.stat.exists
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_groupowner_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

Rule   Verify /boot/grub2/grub.cfg Permissions   [ref]

File permissions for /boot/grub2/grub.cfg should be set to 600. To properly set the permissions of /boot/grub2/grub.cfg, run the command:

$ sudo chmod 600 /boot/grub2/grub.cfg

Rationale:

Proper permissions ensure that only the root user can modify important boot parameters.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_file_permissions_grub2_cfg
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5



Complexity:low
Disruption:low
Strategy:configure

chmod 0600 /boot/grub2/grub.cfg


Complexity:low
Disruption:low
Strategy:configure
- name: Test for existence /boot/grub2/grub.cfg
  stat:
    path: /boot/grub2/grub.cfg
  register: file_exists
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - configure_strategy
    - file_permissions_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

- name: Ensure permission 0600 on /boot/grub2/grub.cfg
  file:
    path: /boot/grub2/grub.cfg
    mode: '0600'
  when:
    - file_exists.stat is defined and file_exists.stat.exists
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - configure_strategy
    - file_permissions_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

Rule   Set the UEFI Boot Loader Password   [ref]

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

Since plaintext passwords are a security risk, generate a hash for the pasword by running the following command:

$ grub2-setpassword
When prompted, enter the password that was selected.

Once the superuser password has been added, update the grub.cfg file by running:
grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

Warning:  To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above. Also, do NOT manually add the superuser account and password to the grub.cfg file as the grub2-mkconfig command overwrites this file.
Rationale:

Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_grub2_uefi_password
Identifiers and References

References:  NT28(R17), 1.4.2, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_AFL.1, SRG-OS-000080-GPOS-00048

Rule   Verify the UEFI Boot Loader grub.cfg User Ownership   [ref]

The file /boot/efi/EFI/redhat/grub.cfg should be owned by the root user to prevent destruction or modification of the file. To properly set the owner of /boot/efi/EFI/redhat/grub.cfg, run the command:

$ sudo chown root /boot/efi/EFI/redhat/grub.cfg 

Rationale:

Only root should be able to modify important boot parameters.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_file_owner_efi_grub2_cfg
Identifiers and References

References:  1.4.1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1



Complexity:low
Disruption:low
Strategy:configure


chown 0 /boot/efi/EFI/redhat/grub.cfg


Complexity:low
Disruption:low
Strategy:configure
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
  stat:
    path: /boot/efi/EFI/redhat/grub.cfg
  register: file_exists
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_owner_efi_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

- name: Ensure owner 0 on /boot/efi/EFI/redhat/grub.cfg
  file:
    path: /boot/efi/EFI/redhat/grub.cfg
    owner: '0'
  when:
    - file_exists.stat is defined and file_exists.stat.exists
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_owner_efi_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

Rule   Verify the UEFI Boot Loader grub.cfg Permissions   [ref]

File permissions for /boot/efi/EFI/redhat/grub.cfg should be set to 700. To properly set the permissions of /boot/efi/EFI/redhat/grub.cfg, run the command:

$ sudo chmod 700 /boot/efi/EFI/redhat/grub.cfg

Rationale:

Proper permissions ensure that only the root user can modify important boot parameters.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_file_permissions_efi_grub2_cfg
Identifiers and References

References:  1.4.1, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5



chmod 700 /boot/efi/EFI/redhat/grub.cfg


Complexity:low
Disruption:low
Strategy:configure
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
  stat:
    path: /boot/efi/EFI/redhat/grub.cfg
  register: file_exists
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - configure_strategy
    - file_permissions_efi_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

- name: Ensure permission 0700 on /boot/efi/EFI/redhat/grub.cfg
  file:
    path: /boot/efi/EFI/redhat/grub.cfg
    mode: '0700'
  when:
    - file_exists.stat is defined and file_exists.stat.exists
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - configure_strategy
    - file_permissions_efi_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

Rule   Set Boot Loader Password in grub2   [ref]

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

Since plaintext passwords are a security risk, generate a hash for the pasword by running the following command:

$ grub2-setpassword
When prompted, enter the password that was selected.

Once the superuser password has been added, update the grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg

Warning:  To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above. Also, do NOT manually add the superuser account and password to the grub.cfg file as the grub2-mkconfig command overwrites this file.
Rationale:

Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_grub2_password
Identifiers and References

References:  NT28(R17), 1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_AFL.1, SRG-OS-000080-GPOS-00048

Rule   Verify /boot/grub2/grub.cfg User Ownership   [ref]

The file /boot/grub2/grub.cfg should be owned by the root user to prevent destruction or modification of the file. To properly set the owner of /boot/grub2/grub.cfg, run the command:

$ sudo chown root /boot/grub2/grub.cfg 

Rationale:

Only root should be able to modify important boot parameters.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_file_owner_grub2_cfg
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1



Complexity:low
Disruption:low
Strategy:configure


chown 0 /boot/grub2/grub.cfg


Complexity:low
Disruption:low
Strategy:configure
- name: Test for existence /boot/grub2/grub.cfg
  stat:
    path: /boot/grub2/grub.cfg
  register: file_exists
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_owner_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

- name: Ensure owner 0 on /boot/grub2/grub.cfg
  file:
    path: /boot/grub2/grub.cfg
    owner: '0'
  when:
    - file_exists.stat is defined and file_exists.stat.exists
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_owner_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

Rule   Verify the UEFI Boot Loader grub.cfg Group Ownership   [ref]

The file /boot/efi/EFI/redhat/grub.cfg should be group-owned by the root group to prevent destruction or modification of the file. To properly set the group owner of /boot/efi/EFI/redhat/grub.cfg, run the command:

$ sudo chgrp root /boot/efi/EFI/redhat/grub.cfg

Rationale:

The root group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_file_groupowner_efi_grub2_cfg
Identifiers and References

References:  1.4.1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1



Complexity:low
Disruption:low
Strategy:configure


chgrp 0 /boot/efi/EFI/redhat/grub.cfg


Complexity:low
Disruption:low
Strategy:configure
- name: Test for existence /boot/efi/EFI/redhat/grub.cfg
  stat:
    path: /boot/efi/EFI/redhat/grub.cfg
  register: file_exists
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_groupowner_efi_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed

- name: Ensure group owner 0 on /boot/efi/EFI/redhat/grub.cfg
  file:
    path: /boot/efi/EFI/redhat/grub.cfg
    group: '0'
  when:
    - file_exists.stat is defined and file_exists.stat.exists
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.2.2
    - NIST-800-171-3.4.5
    - NIST-800-53-AC-6(1)
    - NIST-800-53-CM-6(a)
    - PCI-DSS-Req-7.1
    - configure_strategy
    - file_groupowner_efi_grub2_cfg
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
Group   File Permissions and Masks   Group contains 4 groups and 5 rules

[ref]   Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access.

Several of the commands in this section search filesystems for files or directories with certain characteristics, and are intended to be run on every local partition on a given system. When the variable PART appears in one of the commands below, it means that the command is intended to be run repeatedly, with the name of each local partition substituted for PART in turn.

The following command prints a list of all xfs partitions on the local system, which is the default filesystem for Oracle Linux 8 installations:

$ mount -t xfs | awk '{print $3}'
For any systems that use a different local filesystem type, modify this command as appropriate.

Group   Restrict Dynamic Mounting and Unmounting of Filesystems   Group contains 2 rules

[ref]   Linux includes a number of facilities for the automated addition and removal of filesystems on a running system. These facilities may be necessary in many environments, but this capability also carries some risk -- whether direct risk from allowing users to introduce arbitrary filesystems, or risk that software flaws in the automated mount facility itself could allow an attacker to compromise the system.

This command can be used to list the types of filesystems that are available to the currently executing kernel:

$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
If these filesystems are not required then they can be explicitly disabled in a configuratio file in /etc/modprobe.d.

Rule   Disable the Automounter   [ref]

The autofs daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as /misc/cd. However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it may be possible to configure filesystem mounts statically by editing /etc/fstab rather than relying on the automounter.

The autofs service can be disabled with the following command:

$ sudo systemctl disable autofs.service
The autofs service can be masked with the following command:
$ sudo systemctl mask autofs.service

Rationale:

Disabling the automounter permits the administrator to statically control filesystem mounting through /etc/fstab.

Additionally, automatically mounting filesystems permits easy introduction of unknown devices, thereby facilitating malicious activity.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_service_autofs_disabled
Identifiers and References

References:  1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.4.6, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'autofs.service'
"$SYSTEMCTL_EXEC" disable 'autofs.service'
"$SYSTEMCTL_EXEC" mask 'autofs.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^autofs.socket'; then
    "$SYSTEMCTL_EXEC" stop 'autofs.socket'
    "$SYSTEMCTL_EXEC" disable 'autofs.socket'
    "$SYSTEMCTL_EXEC" mask 'autofs.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'autofs.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service autofs
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service autofs
      systemd:
        name: autofs.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"autofs.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.6
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-MP-7
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_autofs_disabled

- name: Unit Socket Exists - autofs.socket
  command: systemctl list-unit-files autofs.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.6
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-MP-7
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_autofs_disabled

- name: Disable socket autofs
  systemd:
    name: autofs.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"autofs.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.6
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-MP-7
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_autofs_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_autofs

class disable_autofs {
  service {'autofs':
    enable => false,
    ensure => 'stopped',
  }
}

Rule   Disable Modprobe Loading of USB Storage Driver   [ref]

To prevent USB storage devices from being used, configure the kernel module loading system to prevent automatic loading of the USB storage driver. To configure the system to prevent the usb-storage kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d:

install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage module, but will not prevent an administrator (or another program) from using the insmod program to load the module manually.

Rationale:

USB storage devices such as thumb drives can be used to introduce malicious software.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_kernel_module_usb-storage_disabled
Identifiers and References

References:  1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.21, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-0016, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
if LC_ALL=C grep -q -m 1 "^install usb-storage" /etc/modprobe.d/usb-storage.conf ; then
	sed -i 's/^install usb-storage.*/install usb-storage /bin/true/g' /etc/modprobe.d/usb-storage.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/usb-storage.conf
	echo "install usb-storage /bin/true" >> /etc/modprobe.d/usb-storage.conf
fi


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
- name: Ensure kernel module 'usb-storage' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/usb-storage.conf
    regexp: usb-storage
    line: install usb-storage /bin/true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.21
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-MP-7
    - disable_strategy
    - kernel_module_usb-storage_disabled
    - low_complexity
    - medium_disruption
    - medium_severity
    - reboot_required
Group   Restrict Programs from Dangerous Execution Patterns   Group contains 2 groups and 3 rules

[ref]   The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution are activated. These protections are applied at the system initialization or kernel level, and defend against certain types of badly-configured or compromised programs.

Group   Disable Core Dumps   Group contains 1 rule

[ref]   A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases, only software developers legitimately need to access these files. The core dump files may also contain sensitive information, or unnecessarily occupy large amounts of disk space.

Once a hard limit is set in /etc/security/limits.conf, or to a file within the /etc/security/limits.d/ directory, a user cannot increase that limit within his or her own session. If access to core dumps is required, consider restricting them to only certain users or groups. See the limits.conf man page for more information.

The core dumps of setuid programs are further protected. The sysctl variable fs.suid_dumpable controls whether the kernel allows core dumps from these programs at all. The default value of 0 is recommended.

Rule   Disable Core Dumps for SUID programs   [ref]

To set the runtime status of the fs.suid_dumpable kernel parameter, run the following command:

$ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
fs.suid_dumpable = 0

Rationale:

The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sysctl_fs_suid_dumpable
Identifiers and References

References:  NT28(R23), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b)



Complexity:low
Disruption:medium
Reboot:true
Strategy:disable


#
# Set runtime for fs.suid_dumpable
#
/sbin/sysctl -q -n -w fs.suid_dumpable="0"

#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
#	else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/sysctl.conf' '^fs.suid_dumpable' "0" ''


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
- name: Ensure sysctl fs.suid_dumpable is set to 0
  sysctl:
    name: fs.suid_dumpable
    value: '0'
    state: present
    reload: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-SI-11(a)
    - NIST-800-53-SI-11(b)
    - disable_strategy
    - low_complexity
    - medium_disruption
    - medium_severity
    - reboot_required
    - sysctl_fs_suid_dumpable
Group   Enable ExecShield   Group contains 1 rule

[ref]   ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These features include random placement of the stack and other memory regions, prevention of execution in memory that should only hold data, and special handling of text buffers. These protections are enabled by default on 32-bit systems and controlled through sysctl variables kernel.exec-shield and kernel.randomize_va_space. On the latest 64-bit systems, kernel.exec-shield cannot be enabled or disabled with sysctl.

Rule   Enable Randomized Layout of Virtual Address Space   [ref]

To set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command:

$ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.randomize_va_space = 2

Rationale:

Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sysctl_kernel_randomize_va_space
Identifiers and References

References:  NT28(R23), 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SC-30, SC-30(2), CM-6(a), SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:medium
Reboot:true
Strategy:disable


#
# Set runtime for kernel.randomize_va_space
#
/sbin/sysctl -q -n -w kernel.randomize_va_space="2"

#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
#	else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' "2" ''


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
- name: Ensure sysctl kernel.randomize_va_space is set to 2
  sysctl:
    name: kernel.randomize_va_space
    value: '2'
    state: present
    reload: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-30
    - NIST-800-53-SC-30(2)
    - disable_strategy
    - low_complexity
    - medium_disruption
    - medium_severity
    - reboot_required
    - sysctl_kernel_randomize_va_space

Rule   Restrict Access to Kernel Message Buffer   [ref]

To set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command:

$ sudo sysctl -w kernel.dmesg_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.dmesg_restrict = 1

Rationale:

Unprivileged access to the kernel syslog can expose sensitive kernel address information.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sysctl_kernel_dmesg_restrict
Identifiers and References

References:  NT28(R23), 3.1.5, CCI-001314, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b), SRG-OS-000132-GPOS-00067



Complexity:low
Disruption:medium
Reboot:true
Strategy:disable


#
# Set runtime for kernel.dmesg_restrict
#
/sbin/sysctl -q -n -w kernel.dmesg_restrict="1"

#
# If kernel.dmesg_restrict present in /etc/sysctl.conf, change value to "1"
#	else, add "kernel.dmesg_restrict = 1" to /etc/sysctl.conf
#
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/sysctl.conf' '^kernel.dmesg_restrict' "1" ''


Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
- name: Ensure sysctl kernel.dmesg_restrict is set to 1
  sysctl:
    name: kernel.dmesg_restrict
    value: '1'
    state: present
    reload: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.5
    - NIST-800-53-SI-11(a)
    - NIST-800-53-SI-11(b)
    - disable_strategy
    - low_complexity
    - medium_disruption
    - medium_severity
    - reboot_required
    - sysctl_kernel_dmesg_restrict
Group   SELinux   Group contains 1 group and 7 rules

[ref]   SELinux is a feature of the Linux kernel which can be used to guard against misconfigured or compromised programs. SELinux enforces the idea that programs should be limited in what files they can access and what actions they can take.

The default SELinux policy, as configured on Oracle Linux 8, has been sufficiently developed and debugged that it should be usable on almost any system with minimal configuration and a small amount of system administrator training. This policy prevents system services - including most of the common network-visible services such as mail servers, FTP servers, and DNS servers - from accessing files which those services have no valid reason to access. This action alone prevents a huge amount of possible damage from network attacks against services, from trojaned software, and so forth.

This guide recommends that SELinux be enabled using the default (targeted) policy on every Oracle Linux 8 system, unless that system has unusual requirements which make a stronger policy appropriate.

Group   SELinux - Booleans   Group contains 3 rules

[ref]   Enable or Disable runtime customization of SELinux system policies without having to reload or recompile the SELinux policy.

Rule   Enable the selinuxuser_execmod SELinux Boolean   [ref]

By default, the SELinux boolean selinuxuser_execmod is enabled. If this setting is disabled, it should be enabled. To enable the selinuxuser_execmod SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execmod on

Rationale:

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execmod
Identifiers and References

References:  164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)



Complexity:low
Disruption:low
Strategy:enable

var_selinuxuser_execmod="true"

setsebool -P selinuxuser_execmod $var_selinuxuser_execmod


Complexity:low
Disruption:low
Strategy:enable
- name: XCCDF Value var_selinuxuser_execmod # promote to variable
  set_fact:
    var_selinuxuser_execmod: !!str true
  tags:
    - always

- name: Ensure libsemanage-python installed
  package:
    name: libsemanage-python
    state: present
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - sebool_selinuxuser_execmod

- name: Set SELinux boolean selinuxuser_execmod accordingly
  seboolean:
    name: selinuxuser_execmod
    state: '{{ var_selinuxuser_execmod }}'
    persistent: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - sebool_selinuxuser_execmod

Rule   Disable the selinuxuser_execheap SELinux Boolean   [ref]

By default, the SELinux boolean selinuxuser_execheap is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_execheap SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execheap off

Rationale:

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execheap
Identifiers and References

References:  164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)



Complexity:low
Disruption:low
Strategy:enable

var_selinuxuser_execheap="false"

setsebool -P selinuxuser_execheap $var_selinuxuser_execheap


Complexity:low
Disruption:low
Strategy:enable
- name: XCCDF Value var_selinuxuser_execheap # promote to variable
  set_fact:
    var_selinuxuser_execheap: !!str false
  tags:
    - always

- name: Ensure libsemanage-python installed
  package:
    name: libsemanage-python
    state: present
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - sebool_selinuxuser_execheap

- name: Set SELinux boolean selinuxuser_execheap accordingly
  seboolean:
    name: selinuxuser_execheap
    state: '{{ var_selinuxuser_execheap }}'
    persistent: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - sebool_selinuxuser_execheap

Rule   disable the selinuxuser_execstack SELinux Boolean   [ref]

By default, the SELinux boolean selinuxuser_execstack is enabled. This setting should be disabled as unconfined executables should not be able to make their stack executable. To disable the selinuxuser_execstack SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execstack off

Rationale:

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execstack
Identifiers and References

References:  164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)



Complexity:low
Disruption:low
Strategy:enable

var_selinuxuser_execstack="false"

setsebool -P selinuxuser_execstack $var_selinuxuser_execstack


Complexity:low
Disruption:low
Strategy:enable
- name: XCCDF Value var_selinuxuser_execstack # promote to variable
  set_fact:
    var_selinuxuser_execstack: !!str false
  tags:
    - always

- name: Ensure libsemanage-python installed
  package:
    name: libsemanage-python
    state: present
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - sebool_selinuxuser_execstack

- name: Set SELinux boolean selinuxuser_execstack accordingly
  seboolean:
    name: selinuxuser_execstack
    state: '{{ var_selinuxuser_execstack }}'
    persistent: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - sebool_selinuxuser_execstack

Rule   Ensure SELinux Not Disabled in /etc/default/grub   [ref]

SELinux can be disabled at boot time by an argument in /etc/default/grub. Remove any instances of selinux=0 from the kernel arguments in that file to prevent SELinux from being disabled at boot.

Rationale:

Disabling a major host protection feature, such as SELinux, at boot time prevents it from confining system services at boot time. Further, it increases the chances that it will remain off during system operation.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_grub2_enable_selinux
Identifiers and References

References:  1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-000022, CCI-000032, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-3, AC-3(3)(a), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-VMM-001780




sed -i --follow-symlinks "s/selinux=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
sed -i --follow-symlinks "s/enforcing=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*


Complexity:low
Disruption:low
Strategy:restrict
- name: Find /etc/grub.d/ files
  find:
    paths:
      - /etc/grub.d/
    follow: true
  register: grub
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.2
    - NIST-800-171-3.7.2
    - NIST-800-53-AC-3
    - NIST-800-53-AC-3(3)(a)
    - grub2_enable_selinux
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

- name: Ensure SELinux Not Disabled in grub files
  replace:
    dest: '{{ item.path }}'
    regexp: (selinux|enforcing)=0
  with_items:
    - '{{ grub.files }}'
    - path: /etc/grub2.cfg
    - path: /etc/default/grub
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.2
    - NIST-800-171-3.7.2
    - NIST-800-53-AC-3
    - NIST-800-53-AC-3(3)(a)
    - grub2_enable_selinux
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Configure SELinux Policy   [ref]

The SELinux targeted policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in /etc/selinux/config:

SELINUXTYPE=targeted
Other policies, such as mls, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

Rationale:

Setting the SELinux policy to targeted or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services.

Note: During the development or debugging of SELinux modules, it is common to temporarily place non-production systems in permissive mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to targeted.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_selinux_policytype
Identifiers and References

References:  NT28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000445-VMM-001780



Complexity:low
Disruption:low
Reboot:true
Strategy:restrict

var_selinux_policy_name="targeted"

if [ -e "/etc/selinux/config" ] ; then
    LC_ALL=C sed -i "/^SELINUXTYPE=/Id" "/etc/selinux/config"
else
    touch "/etc/selinux/config"
fi
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUXTYPE=$var_selinux_policy_name" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"


Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
- name: XCCDF Value var_selinux_policy_name # promote to variable
  set_fact:
    var_selinux_policy_name: !!str targeted
  tags:
    - always

- name: Configure SELinux Policy
  block:

    - name: Deduplicate values from /etc/selinux/config
      lineinfile:
        path: /etc/selinux/config
        create: false
        regexp: ^SELINUXTYPE=
        state: absent

    - name: Insert correct line to /etc/selinux/config
      lineinfile:
        path: /etc/selinux/config
        create: true
        line: SELINUXTYPE={{ var_selinux_policy_name }}
        state: present
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.2
    - NIST-800-171-3.7.2
    - NIST-800-53-AC-3
    - NIST-800-53-AC-3(3)(a)
    - NIST-800-53-AU-9
    - NIST-800-53-SC-7(21)
    - high_severity
    - low_complexity
    - low_disruption
    - reboot_required
    - restrict_strategy
    - selinux_policytype

Rule   Ensure No Daemons are Unconfined by SELinux   [ref]

Daemons for which the SELinux policy does not contain rules will inherit the context of the parent process. Because daemons are launched during startup and descend from the init process, they inherit the initrc_t context.

To check for unconfined daemons, run the following command:

$ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'
It should produce no output in a well-configured system.

Warning:  Automatic remediation of this control is not available. Remediation can be achieved by amending SELinux policy or stopping the unconfined daemons as outlined above.
Rationale:

Daemons which run with the initrc_t context may cause AVC denials, or allow privileges that the daemon does not require.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_selinux_confinement_of_daemons
Identifiers and References

References:  1.7.1.5, 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01, 3.1.2, 3.1.5, 3.7.2, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6, PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-3

Rule   Ensure SELinux State is Enforcing   [ref]

The SELinux state should be set to enforcing at system boot time. In the file /etc/selinux/config, add or correct the following line to configure the system to boot into enforcing mode:

SELINUX=enforcing

Rationale:

Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_selinux_state
Identifiers and References

References:  NT28(R4), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000445-VMM-001780



Complexity:low
Disruption:low
Strategy:restrict
- name: XCCDF Value var_selinux_state # promote to variable
  set_fact:
    var_selinux_state: !!str enforcing
  tags:
    - always

- name: Ensure SELinux State is Enforcing
  block:

    - name: Deduplicate values from /etc/selinux/config
      lineinfile:
        path: /etc/selinux/config
        create: false
        regexp: ^SELINUX=
        state: absent

    - name: Insert correct line to /etc/selinux/config
      lineinfile:
        path: /etc/selinux/config
        create: true
        line: SELINUX={{ var_selinux_state }}
        state: present
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.2
    - NIST-800-171-3.7.2
    - NIST-800-53-AC-3
    - NIST-800-53-AC-3(3)(a)
    - NIST-800-53-AU-9
    - NIST-800-53-SC-7(21)
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - restrict_strategy
    - selinux_state
Group   Network Configuration and Firewalls   Group contains 1 group and 1 rule

[ref]   Most systems must be connected to a network of some sort, and this brings with it the substantial risk of network attack. This section discusses the security impact of decisions about networking which must be made when configuring a system.

This section also discusses firewalls, network access controls, and other network security frameworks, which allow system-level rules to be written that can limit an attackers' ability to connect to your system. These rules can specify that network traffic should be allowed or denied from certain IP addresses, hosts, and networks. The rules can also specify which of the system's network services are available to particular hosts or networks.

Group   IPSec Support   Group contains 1 rule

[ref]   Support for Internet Protocol Security (IPsec)

Rule   Verify Any Configured IPSec Tunnel Connections   [ref]

Libreswan provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. As such, IPsec can be used to circumvent certain network requirements such as filtering. Verify that if any IPsec connection (conn) configured in /etc/ipsec.conf and /etc/ipsec.d exists is an approved organizational connection.

Rationale:

IP tunneling mechanisms can be used to bypass network filtering.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_libreswan_approved_tunnels
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, CCI-000336, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), MA-4(6), CM-6(a), AC-4, SC-8, DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227

Group   Configure Syslog   Group contains 1 group and 1 rule

[ref]   The syslog service has been the default Unix logging mechanism for many years. It has a number of downsides, including inconsistent log format, lack of authentication for received messages, and lack of authentication, encryption, or reliable transport for messages sent over a network. However, due to its long history, syslog is a de facto standard which is supported by almost all Unix applications.

In Oracle Linux 8, rsyslog has replaced ksyslogd as the syslog daemon of choice, and it includes some additional security features such as reliable, connection-oriented (i.e. TCP) transmission of logs, the option to log to database formats, and the encryption of log data en route to a central logging server. This section discusses how to configure rsyslog for best effect, and how to use tools provided with the system to maintain and monitor logs.

Group   Rsyslog Logs Sent To Remote Host   Group contains 1 rule

[ref]   If system logs are to be useful in detecting malicious activities, it is necessary to send logs to a remote server. An intruder who has compromised the root account on a system may delete the log entries which indicate that the system was attacked before they are seen by an administrator.

However, it is recommended that logs be stored on the local host in addition to being sent to the loghost, especially if rsyslog has been configured to use the UDP protocol to send messages over a network. UDP does not guarantee reliable delivery, and moderately busy sites will lose log messages occasionally, especially in periods of high traffic which may be the result of an attack. In addition, remote rsyslog messages are not authenticated in any way by default, so it is easy for an attacker to introduce spurious messages to the central log server. Also, some problems cause loss of network connectivity, which will prevent the sending of messages to the central server. For all of these reasons, it is better to store log messages both centrally and on each host, so that they can be correlated if necessary.

Rule   Ensure Logs Sent To Remote Host   [ref]

To configure rsyslog to send logs to a remote log server, open /etc/rsyslog.conf and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting logcollector appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments.
To use UDP for log message delivery:

*.* @logcollector

To use TCP for log message delivery:
*.* @@logcollector

To use RELP for log message delivery:
*.* :omrelp:logcollector

There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.

Rationale:

A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_rsyslog_remote_loghost
Identifiers and References

References:  NT28(R7), NT28(R43), NT12(R5), 1, 13, 14, 15, 16, 2, 3, 5, 6, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001348, CCI-000136, CCI-001851, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.17.2.1, CM-6(a), AU-4(1), AU-9(2), PR.DS-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000480-GPOS-00227, SRG-OS-000032-VMM-000130




rsyslog_remote_loghost_address="logcollector"
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/rsyslog.conf' '^\*\.\*' "@@$rsyslog_remote_loghost_address" '' '%s %s'


Complexity:low
Disruption:low
Strategy:restrict
- name: XCCDF Value rsyslog_remote_loghost_address # promote to variable
  set_fact:
    rsyslog_remote_loghost_address: !!str logcollector
  tags:
    - always

- name: Set rsyslog remote loghost
  lineinfile:
    dest: /etc/rsyslog.conf
    regexp: ^\*\.\*
    line: '*.* @@{{ rsyslog_remote_loghost_address }}'
    create: true
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-AU-4(1)
    - NIST-800-53-AU-9(2)
    - NIST-800-53-CM-6(a)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - rsyslog_remote_loghost
Group   Services   Group contains 13 groups and 27 rules

[ref]   The best protection against vulnerable software is running less software. This section describes how to review the software which Oracle Linux 8 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default Oracle Linux 8 system and provides guidance about which ones can be safely disabled.

Oracle Linux 8 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building Oracle Linux 8 systems, it is highly recommended to select the minimal packages and then build up the system from there.

Group   Cron and At Daemons   Group contains 1 rule

[ref]   The cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively.

Rule   Enable cron Service   [ref]

The crond service is used to execute commands at preconfigured times. It is required by almost all systems to perform necessary maintenance tasks, such as notifying root of system activity. The crond service can be enabled with the following command:

$ sudo systemctl enable crond.service

Rationale:

Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_service_crond_enabled
Identifiers and References

References:  11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-6(a), PR.IP-1, PR.PT-3



Complexity:low
Disruption:low
Strategy:enable

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" start 'crond.service'
"$SYSTEMCTL_EXEC" enable 'crond.service'


Complexity:low
Disruption:low
Strategy:enable
- name: Enable service crond
  block:

    - name: Gather the package facts
      package_facts:
        manager: auto

    - name: Enable service crond
      service:
        name: crond
        enabled: 'yes'
        state: started
      when:
        - '"cronie" in ansible_facts.packages'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - enable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_crond_enabled


Complexity:low
Disruption:low
Strategy:enable
include enable_crond

class enable_crond {
  service {'crond':
    enable => true,
    ensure => 'running',
  }
}
Group   Network Routing   Group contains 1 group and 1 rule

[ref]   A router is a very desirable target for a potential adversary because they fulfill a variety of infrastructure networking roles such as access to network segments, gateways to other networks, filtering, etc. Therefore, if one is required, the system acting as a router should be dedicated to that purpose alone and be stored in a physically secure location. The system's default routing software is Quagga, and provided in an RPM package of the same name.

Group   Disable Quagga if Possible   Group contains 1 rule

[ref]   If Quagga was installed and activated, but the system does not need to act as a router, then it should be disabled and removed.

Rule   Disable Quagga Service   [ref]

The zebra service can be disabled with the following command:

$ sudo systemctl disable zebra.service
The zebra service can be masked with the following command:
$ sudo systemctl mask zebra.service

Rationale:

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If routing daemons are used when not required, system network information may be unnecessarily transmitted across the network.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_service_zebra_disabled
Identifiers and References

References:  12, 15, 8, APO13.01, DSS05.02, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-7(a), CM-7(b), CM-6(a), PR.PT-4, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'zebra.service'
"$SYSTEMCTL_EXEC" disable 'zebra.service'
"$SYSTEMCTL_EXEC" mask 'zebra.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^zebra.socket'; then
    "$SYSTEMCTL_EXEC" stop 'zebra.socket'
    "$SYSTEMCTL_EXEC" disable 'zebra.socket'
    "$SYSTEMCTL_EXEC" mask 'zebra.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'zebra.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service zebra
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service zebra
      systemd:
        name: zebra.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"zebra.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_zebra_disabled

- name: Unit Socket Exists - zebra.socket
  command: systemctl list-unit-files zebra.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_zebra_disabled

- name: Disable socket zebra
  systemd:
    name: zebra.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"zebra.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_zebra_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_zebra

class disable_zebra {
  service {'zebra':
    enable => false,
    ensure => 'stopped',
  }
}
Group   SSH Server   Group contains 1 group and 12 rules

[ref]   The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, through the use of public key cryptography. The implementation included with the system is called OpenSSH, and more detailed documentation is available from its website, https://www.openssh.com. Its server program is called sshd and provided by the RPM package openssh-server.

Group   Configure OpenSSH Server if Necessary   Group contains 12 rules

[ref]   If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file /etc/ssh/sshd_config. The following recommendations can be applied to this file. See the sshd_config(5) man page for more detailed information.

Rule   Allow Only SSH Protocol 2   [ref]

Only SSH protocol version 2 connections should be permitted. The default setting in /etc/ssh/sshd_config is correct, and can be verified by ensuring that the following line appears:

Protocol 2

Warning:  As of openssh-server version 7.4 and above, the only protocol supported is version 2, and line
Protocol 2
in /etc/ssh/sshd_config is not necessary.
Rationale:

SSH protocol version 1 is an insecure implementation of the SSH protocol and has many well-known vulnerability exploits. Exploits of the SSH daemon could provide immediate root access to the system.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_sshd_allow_only_protocol2
Identifiers and References

References:  NT007(R1), 5.2.2, 1, 12, 15, 16, 5, 8, 5.5.6, APO13.01, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.13, 3.5.4, CCI-000197, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-17(a), AC-17(2), IA-5(1)(c), SC-13, MA-4(6), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.PT-4, SRG-OS-000074-GPOS-00042, SRG-OS-000480-GPOS-00227, SRG-OS-000033-VMM-000140



# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/ssh/sshd_config' '^Protocol' '2' '' '%s %s'


Complexity:low
Disruption:low
Strategy:restrict
- name: Allow Only SSH Protocol 2
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*Protocol\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: Protocol 2
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.6
    - NIST-800-171-3.1.13
    - NIST-800-171-3.5.4
    - NIST-800-53-AC-17(2)
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-IA-5(1)(c)
    - NIST-800-53-MA-4(6)
    - NIST-800-53-SC-13
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - restrict_strategy
    - sshd_allow_only_protocol2

Rule   Disable SSH Access via Empty Passwords   [ref]

To explicitly disallow SSH login from accounts with empty passwords, add or correct the following line in /etc/ssh/sshd_config:

PermitEmptyPasswords no

Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.

Rationale:

Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_sshd_disable_empty_passwords
Identifiers and References

References:  NT007(R17), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_AFL.1, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Disable SSH Access via Empty Passwords
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*PermitEmptyPasswords\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: PermitEmptyPasswords no
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.6
    - NIST-800-171-3.1.1
    - NIST-800-171-3.1.5
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - restrict_strategy
    - sshd_disable_empty_passwords


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Enable SSH Warning Banner   [ref]

To enable the warning banner and ensure it is consistent across the system, add or correct the following line in /etc/ssh/sshd_config:

Banner /etc/issue
Another section contains information on how to create an appropriate system-wide warning banner.

Rationale:

The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_enable_warning_banner
Identifiers and References

References:  1, 12, 15, 16, 5.5.6, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), AC-17(a), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SRG-OS-000228-GPOS-00088, SRG-OS-000023-VMM-000060, SRG-OS-000024-VMM-000070



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "Banner /etc/issue" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "Banner /etc/issue" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Enable SSH Warning Banner
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*Banner\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: Banner /etc/issue
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.6
    - NIST-800-171-3.1.9
    - NIST-800-53-AC-17(a)
    - NIST-800-53-AC-8(a)
    - NIST-800-53-AC-8(c)
    - NIST-800-53-CM-6(a)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_enable_warning_banner


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Disable Host-Based Authentication   [ref]

SSH's cryptographic host-based authentication is more secure than .rhosts authentication. However, it is not recommended that hosts unilaterally trust one another, even within an organization.

To disable host-based authentication, add or correct the following line in /etc/ssh/sshd_config:

HostbasedAuthentication no

Rationale:

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_disable_host_auth
Identifiers and References

References:  11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-3, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_AFL.1, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "HostbasedAuthentication no" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "HostbasedAuthentication no" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Disable Host-Based Authentication
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*HostbasedAuthentication\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: HostbasedAuthentication no
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.6
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-AC-3
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_host_auth
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy

Rule   Disable Compression Or Set Compression to delayed   [ref]

Compression is useful for slow network connections over long distances but can cause performance issues on local LANs. If use of compression is required, it should be enabled only after a user has authenticated; otherwise, it should be disabled. To disable compression or delay compression until after a user has successfully authenticated, add or correct the following line in the /etc/ssh/sshd_config file:

Compression no

Rationale:

If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_disable_compression
Identifiers and References

References:  11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000




var_sshd_disable_compression="no"
# Function to replace configuration setting in config file or add the configuration setting if
# it does not exist.
#
# Expects arguments:
#
# config_file:		Configuration file that will be modified
# key:			Configuration option to change
# value:		Value of the configuration option to change
# cce:			The CCE identifier or '@CCENUM@' if no CCE identifier exists
# format:		The printf-like format string that will be given stripped key and value as arguments,
#			so e.g. '%s=%s' will result in key=value subsitution (i.e. without spaces around =)
#
# Optional arugments:
#
# format:		Optional argument to specify the format of how key/value should be
# 			modified/appended in the configuration file. The default is key = value.
#
# Example Call(s):
#
#     With default format of 'key = value':
#     replace_or_append '/etc/sysctl.conf' '^kernel.randomize_va_space' '2' '@CCENUM@'
#
#     With custom key/value format:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' 'disabled' '@CCENUM@' '%s=%s'
#
#     With a variable:
#     replace_or_append '/etc/sysconfig/selinux' '^SELINUX=' $var_selinux_state '@CCENUM@' '%s=%s'
#
function replace_or_append {
  local default_format='%s = %s' case_insensitive_mode=yes sed_case_insensitive_option='' grep_case_insensitive_option=''
  local config_file=$1
  local key=$2
  local value=$3
  local cce=$4
  local format=$5

  if [ "$case_insensitive_mode" = yes ]; then
    sed_case_insensitive_option="i"
    grep_case_insensitive_option="-i"
  fi
  [ -n "$format" ] || format="$default_format"
  # Check sanity of the input
  [ $# -ge "3" ] || { echo "Usage: replace_or_append <config_file_location> <key_to_search> <new_value> [<CCE number or literal '@CCENUM@' if unknown>] [printf-like format, default is '$default_format']" >&2; exit 1; }

  # Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
  # Otherwise, regular sed command will do.
  sed_command=('sed' '-i')
  if test -L "$config_file"; then
    sed_command+=('--follow-symlinks')
  fi

  # Test that the cce arg is not empty or does not equal @CCENUM@.
  # If @CCENUM@ exists, it means that there is no CCE assigned.
  if [ -n "$cce" ] && [ "$cce" != '@CCENUM@' ]; then
    cce="${cce}"
  else
    cce="CCE"
  fi

  # Strip any search characters in the key arg so that the key can be replaced without
  # adding any search characters to the config file.
  stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$key")

  # shellcheck disable=SC2059
  printf -v formatted_output "$format" "$stripped_key" "$value"

  # If the key exists, change it. Otherwise, add it to the config_file.
  # We search for the key string followed by a word boundary (matched by \>),
  # so if we search for 'setting', 'setting2' won't match.
  if LC_ALL=C grep -q -m 1 $grep_case_insensitive_option -e "${key}\\>" "$config_file"; then
    "${sed_command[@]}" "s/${key}\\>.*/$formatted_output/g$sed_case_insensitive_option" "$config_file"
  else
    # \n is precaution for case where file ends without trailing newline
    printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$config_file" >> "$config_file"
    printf '%s\n' "$formatted_output" >> "$config_file"
  fi
}
replace_or_append '/etc/ssh/sshd_config' '^Compression' "$var_sshd_disable_compression" '' '%s %s'


Complexity:low
Disruption:low
Strategy:restrict
- name: Disable Compression Or Set Compression to delayed
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*Compression\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: Compression delayed
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_disable_compression


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Do Not Allow SSH Environment Options   [ref]

To ensure users are not able to override environment variables of the SSH daemon, add or correct the following line in /etc/ssh/sshd_config:

PermitUserEnvironment no

Rationale:

SSH environment options potentially allow users to bypass access restriction in some configurations.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_do_not_permit_user_env
Identifiers and References

References:  11, 3, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00229, SRG-OS-000480-VMM-002000



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Do Not Allow SSH Environment Options
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*PermitUserEnvironment\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: PermitUserEnvironment no
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.6
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_do_not_permit_user_env


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Set SSH Client Alive Max Count   [ref]

To ensure the SSH idle timeout occurs precisely when the ClientAliveInterval is set, edit /etc/ssh/sshd_config as follows:

ClientAliveCountMax 0

Rationale:

This ensures a user login will be terminated as soon as the ClientAliveInterval is reached.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_set_keepalive
Identifiers and References

References:  1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000480-VMM-002000




var_sshd_set_keepalive="0"

if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "ClientAliveCountMax $var_sshd_set_keepalive" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "ClientAliveCountMax $var_sshd_set_keepalive" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: XCCDF Value var_sshd_set_keepalive # promote to variable
  set_fact:
    var_sshd_set_keepalive: !!str 0
  tags:
    - always

- name: Set SSH Client Alive Max Count
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*ClientAliveCountMax\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: ClientAliveCountMax {{ var_sshd_set_keepalive }}
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - CJIS-5.5.6
    - NIST-800-171-3.1.11
    - NIST-800-53-AC-12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-AC-2(5)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-SC-10
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_set_keepalive


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Enable Use of Strict Mode Checking   [ref]

SSHs StrictModes option checks file and ownership permissions in the user's home directory .ssh folder before accepting login. If world- writable permissions are found, logon is rejected. To enable StrictModes in SSH, add or correct the following line in the /etc/ssh/sshd_config file:

StrictModes yes

Rationale:

If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_enable_strictmodes
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6, AC-17(a), CM-6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "StrictModes yes" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "StrictModes yes" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Enable Use of Strict Mode Checking
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*StrictModes\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: StrictModes yes
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-AC-6
    - NIST-800-53-CM-6(a)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_enable_strictmodes


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Disable GSSAPI Authentication   [ref]

Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like GSSAPI. To disable GSSAPI authentication, add or correct the following line in the /etc/ssh/sshd_config file:

GSSAPIAuthentication no

Rationale:

GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_disable_gssapi_auth
Identifiers and References

References:  11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-7(a), CM-7(b), CM-6(a), AC-17(a), PR.IP-1, FIA_AFL.1, SRG-OS-000364-GPOS-00151, SRG-OS-000480-VMM-002000



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*GSSAPIAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "GSSAPIAuthentication no" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "GSSAPIAuthentication no" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Disable GSSAPI Authentication
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*GSSAPIAuthentication\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: GSSAPIAuthentication no
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_disable_gssapi_auth


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Enable Use of Privilege Separation   [ref]

When enabled, SSH will create an unprivileged child process that has the privilege of the authenticated user. To enable privilege separation in SSH, add or correct the following line in the /etc/ssh/sshd_config file:

UsePrivilegeSeparation sandbox

Rationale:

SSH daemon privilege separation causes the SSH process to drop root privileges when not needed which would decrease the impact of software vulnerabilities in the unprivileged section.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_use_priv_separation
Identifiers and References

References:  12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-17(a), AC-6, PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:low
Strategy:restrict

var_sshd_priv_separation="sandbox"

if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*UsePrivilegeSeparation\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "UsePrivilegeSeparation $var_sshd_priv_separation" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "UsePrivilegeSeparation $var_sshd_priv_separation" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Enable Use of Privilege Separation
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*UsePrivilegeSeparation\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: UsePrivilegeSeparation sandbox
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-AC-6
    - NIST-800-53-CM-6(a)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_use_priv_separation


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config

Rule   Disable Kerberos Authentication   [ref]

Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like Kerberos. To disable Kerberos authentication, add or correct the following line in the /etc/ssh/sshd_config file:

KerberosAuthentication no

Rationale:

Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementations may be subject to exploitation.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_sshd_disable_kerb_auth
Identifiers and References

References:  11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, FIA_AFL.1, SRG-OS-000364-GPOS-00151, SRG-OS-000480-VMM-002000



Complexity:low
Disruption:low
Strategy:restrict
if [ -e "/etc/ssh/sshd_config" ] ; then
    LC_ALL=C sed -i "/^\s*KerberosAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^Match', insert at
    # the end of the file.
    printf '%s\n' "KerberosAuthentication no" >> "/etc/ssh/sshd_config"
else
    head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
    printf '%s\n' "KerberosAuthentication no" >> "/etc/ssh/sshd_config"
    tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"


Complexity:low
Disruption:low
Strategy:restrict
- name: Disable Kerberos Authentication
  block:

    - name: Deduplicate values from /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: false
        regexp: (?i)^\s*KerberosAuthentication\s+
        state: absent

    - name: Insert correct line to /etc/ssh/sshd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        create: true
        line: KerberosAuthentication no
        state: present
        insertbefore: ^[#\s]*Match
        validate: /usr/sbin/sshd -t -f %s
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.12
    - NIST-800-53-AC-17(a)
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - restrict_strategy
    - sshd_disable_kerb_auth


Complexity:low
Disruption:low
Strategy:restrict
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:,%0A%23%09%24OpenBSD%3A%20sshd_config%2Cv%201.103%202018/04/09%2020%3A41%3A22%20tj%20Exp%20%24%0A%0A%23%20This%20is%20the%20sshd%20server%20system-wide%20configuration%20file.%20%20See%0A%23%20sshd_config%285%29%20for%20more%20information.%0A%0A%23%20This%20sshd%20was%20compiled%20with%20PATH%3D/usr/local/bin%3A/usr/bin%3A/usr/local/sbin%3A/usr/sbin%0A%0A%23%20The%20strategy%20used%20for%20options%20in%20the%20default%20sshd_config%20shipped%20with%0A%23%20OpenSSH%20is%20to%20specify%20options%20with%20their%20default%20value%20where%0A%23%20possible%2C%20but%20leave%20them%20commented.%20%20Uncommented%20options%20override%20the%0A%23%20default%20value.%0A%0A%23%20If%20you%20want%20to%20change%20the%20port%20on%20a%20SELinux%20system%2C%20you%20have%20to%20tell%0A%23%20SELinux%20about%20this%20change.%0A%23%20semanage%20port%20-a%20-t%20ssh_port_t%20-p%20tcp%20%23PORTNUMBER%0A%23%0A%23Port%2022%0A%23AddressFamily%20any%0A%23ListenAddress%200.0.0.0%0A%23ListenAddress%20%3A%3A%0A%0AHostKey%20/etc/ssh/ssh_host_rsa_key%0AHostKey%20/etc/ssh/ssh_host_ecdsa_key%0AHostKey%20/etc/ssh/ssh_host_ed25519_key%0A%0A%23%20Ciphers%20and%20keying%0ARekeyLimit%20512M%201h%0A%0A%23%20System-wide%20Crypto%20policy%3A%0A%23%20This%20system%20is%20following%20system-wide%20crypto%20policy.%20The%20changes%20to%0A%23%20Ciphers%2C%20MACs%2C%20KexAlgoritms%20and%20GSSAPIKexAlgorithsm%20will%20not%20have%20any%0A%23%20effect%20here.%20They%20will%20be%20overridden%20by%20command-line%20options%20passed%20on%0A%23%20the%20server%20start%20up.%0A%23%20To%20opt%20out%2C%20uncomment%20a%20line%20with%20redefinition%20of%20%20CRYPTO_POLICY%3D%0A%23%20variable%20in%20%20/etc/sysconfig/sshd%20%20to%20overwrite%20the%20policy.%0A%23%20For%20more%20information%2C%20see%20manual%20page%20for%20update-crypto-policies%288%29.%0A%0A%23%20Logging%0A%23SyslogFacility%20AUTH%0ASyslogFacility%20AUTHPRIV%0A%23LogLevel%20INFO%0A%0A%23%20Authentication%3A%0A%0A%23LoginGraceTime%202m%0APermitRootLogin%20no%0AStrictModes%20yes%0A%23MaxAuthTries%206%0A%23MaxSessions%2010%0A%0APubkeyAuthentication%20yes%0A%0A%23%20The%20default%20is%20to%20check%20both%20.ssh/authorized_keys%20and%20.ssh/authorized_keys2%0A%23%20but%20this%20is%20overridden%20so%20installations%20will%20only%20check%20.ssh/authorized_keys%0AAuthorizedKeysFile%09.ssh/authorized_keys%0A%0A%23AuthorizedPrincipalsFile%20none%0A%0A%23AuthorizedKeysCommand%20none%0A%23AuthorizedKeysCommandUser%20nobody%0A%0A%23%20For%20this%20to%20work%20you%20will%20also%20need%20host%20keys%20in%20/etc/ssh/ssh_known_hosts%0AHostbasedAuthentication%20no%0A%23%20Change%20to%20yes%20if%20you%20don%27t%20trust%20~/.ssh/known_hosts%20for%0A%23%20HostbasedAuthentication%0AIgnoreUserKnownHosts%20yes%0A%23%20Don%27t%20read%20the%20user%27s%20~/.rhosts%20and%20~/.shosts%20files%0AIgnoreRhosts%20yes%0A%0A%23%20To%20disable%20tunneled%20clear%20text%20passwords%2C%20change%20to%20no%20here%21%0A%23PasswordAuthentication%20yes%0APermitEmptyPasswords%20no%0APasswordAuthentication%20no%0A%0A%23%20Change%20to%20no%20to%20disable%20s/key%20passwords%0A%23ChallengeResponseAuthentication%20yes%0AChallengeResponseAuthentication%20no%0A%0A%23%20Kerberos%20options%0AKerberosAuthentication%20no%0A%23KerberosOrLocalPasswd%20yes%0A%23KerberosTicketCleanup%20yes%0A%23KerberosGetAFSToken%20no%0A%23KerberosUseKuserok%20yes%0A%0A%23%20GSSAPI%20options%0AGSSAPIAuthentication%20no%0AGSSAPICleanupCredentials%20no%0A%23GSSAPIStrictAcceptorCheck%20yes%0A%23GSSAPIKeyExchange%20no%0A%23GSSAPIEnablek5users%20no%0A%0A%23%20Set%20this%20to%20%27yes%27%20to%20enable%20PAM%20authentication%2C%20account%20processing%2C%0A%23%20and%20session%20processing.%20If%20this%20is%20enabled%2C%20PAM%20authentication%20will%0A%23%20be%20allowed%20through%20the%20ChallengeResponseAuthentication%20and%0A%23%20PasswordAuthentication.%20%20Depending%20on%20your%20PAM%20configuration%2C%0A%23%20PAM%20authentication%20via%20ChallengeResponseAuthentication%20may%20bypass%0A%23%20the%20setting%20of%20%22PermitRootLogin%20without-password%22.%0A%23%20If%20you%20just%20want%20the%20PAM%20account%20and%20session%20checks%20to%20run%20without%0A%23%20PAM%20authentication%2C%20then%20enable%20this%20but%20set%20PasswordAuthentication%0A%23%20and%20ChallengeResponseAuthentication%20to%20%27no%27.%0A%23%20WARNING%3A%20%27UsePAM%20no%27%20is%20not%20supported%20in%20Fedora%20and%20may%20cause%20several%0A%23%20problems.%0AUsePAM%20yes%0A%0A%23AllowAgentForwarding%20yes%0A%23AllowTcpForwarding%20yes%0A%23GatewayPorts%20no%0AX11Forwarding%20yes%0A%23X11DisplayOffset%2010%0A%23X11UseLocalhost%20yes%0A%23PermitTTY%20yes%0A%0A%23%20It%20is%20recommended%20to%20use%20pam_motd%20in%20/etc/pam.d/sshd%20instead%20of%20PrintMotd%2C%0A%23%20as%20it%20is%20more%20configurable%20and%20versatile%20than%20the%20built-in%20version.%0APrintMotd%20no%0A%0APrintLastLog%20yes%0A%23TCPKeepAlive%20yes%0APermitUserEnvironment%20no%0ACompression%20no%0AClientAliveInterval%20600%0AClientAliveCountMax%200%0A%23UseDNS%20no%0A%23PidFile%20/var/run/sshd.pid%0A%23MaxStartups%2010%3A30%3A100%0A%23PermitTunnel%20no%0A%23ChrootDirectory%20none%0A%23VersionAddendum%20none%0A%0A%23%20no%20default%20banner%20path%0ABanner%20/etc/issue%0A%0A%23%20Accept%20locale-related%20environment%20variables%0AAcceptEnv%20LANG%20LC_CTYPE%20LC_NUMERIC%20LC_TIME%20LC_COLLATE%20LC_MONETARY%20LC_MESSAGES%0AAcceptEnv%20LC_PAPER%20LC_NAME%20LC_ADDRESS%20LC_TELEPHONE%20LC_MEASUREMENT%0AAcceptEnv%20LC_IDENTIFICATION%20LC_ALL%20LANGUAGE%0AAcceptEnv%20XMODIFIERS%0A%0A%23%20override%20default%20of%20no%20subsystems%0ASubsystem%09sftp%09/usr/libexec/openssh/sftp-server%0A%0A%23%20Example%20of%20overriding%20settings%20on%20a%20per-user%20basis%0A%23Match%20User%20anoncvs%0A%23%09X11Forwarding%20no%0A%23%09AllowTcpForwarding%20no%0A%23%09PermitTTY%20no%0A%23%09ForceCommand%20cvs%20server%0A%0AUsePrivilegeSeparation%20sandbox
        filesystem: root
        mode: 0600
        path: /etc/ssh/sshd_config
Group   Obsolete Services   Group contains 4 groups and 11 rules

[ref]   This section discusses a number of network-visible services which have historically caused problems for system security, and for which disabling or severely limiting the service has been the best available guidance for some time. As a result of this, many of these services are not installed as part of Oracle Linux 8 by default.

Organizations which are running these services should switch to more secure equivalents as soon as possible. If it remains absolutely necessary to run one of these services for legacy reasons, care should be taken to restrict the service as much as possible, for instance by configuring host firewall software such as iptables to restrict access to the vulnerable service to only those remote hosts which have a known need to use it.

Group   Telnet   Group contains 3 rules

[ref]   The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication information such as passwords. Organizations which use telnet should be actively working to migrate to a more secure protocol.

Rule   Remove telnet Clients   [ref]

The telnet client allows users to start connections to other systems via the telnet protocol.

Rationale:

The telnet protocol is insecure and unencrypted. The use of an unencrypted transmission medium could allow an unauthorized user to steal credentials. The ssh package provides an encrypted session and stronger security and is included in Oracle Linux 8.

Severity: 
low
Rule ID:xccdf_org.ssgproject.content_rule_package_telnet_removed
Identifiers and References

References:  3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3



Complexity:low
Disruption:low
Strategy:disable

# CAUTION: This remediation script will remove telnet
#	   from the system, and may remove any packages
#	   that depend on telnet. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "telnet" ; then
    yum remove -y "telnet"
fi


Complexity:low
Disruption:low
Strategy:disable
- name: Ensure telnet is removed
  package:
    name: telnet
    state: absent
  tags:
    - NIST-800-171-3.1.13
    - disable_strategy
    - low_complexity
    - low_disruption
    - low_severity
    - no_reboot_needed
    - package_telnet_removed


Complexity:low
Disruption:low
Strategy:disable
include remove_telnet

class remove_telnet {
  package { 'telnet':
    ensure => 'purged',
  }
}


Complexity:low
Disruption:low
Strategy:disable

package --remove=telnet

Rule   Uninstall telnet-server Package   [ref]

The telnet-server package can be removed with the following command:

$ sudo yum erase telnet-server

Rationale:

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities are often overlooked and therefore may remain unsecure. They increase the risk to the platform by providing additional attack vectors.
The telnet service provides an unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using this service, the privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the telnet service's accidental (or intentional) activation.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_package_telnet-server_removed
Identifiers and References

References:  2.1.1, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049



Complexity:low
Disruption:low
Strategy:disable

# CAUTION: This remediation script will remove telnet-server
#	   from the system, and may remove any packages
#	   that depend on telnet-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "telnet-server" ; then
    yum remove -y "telnet-server"
fi


Complexity:low
Disruption:low
Strategy:disable
- name: Ensure telnet-server is removed
  package:
    name: telnet-server
    state: absent
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - package_telnet-server_removed


Complexity:low
Disruption:low
Strategy:disable
include remove_telnet-server

class remove_telnet-server {
  package { 'telnet-server':
    ensure => 'purged',
  }
}


Complexity:low
Disruption:low
Strategy:disable

package --remove=telnet-server

Rule   Disable telnet Service   [ref]

The telnet service configuration file /etc/xinetd.d/telnet is not created automatically. If it was created manually, check the /etc/xinetd.d/telnet file and ensure that disable = no is changed to read disable = yes as follows below:

# description: The telnet server serves telnet sessions; it uses \\
#       unencrypted username/password pairs for authentication.
service telnet
{
        flags           = REUSE
        socket_type     = stream

        wait            = no
        user            = root
        server          = /usr/sbin/in.telnetd
        log_on_failure  += USERID
        disable         = yes
}
If the /etc/xinetd.d/telnet file does not exist, make sure that the activation of the telnet service on system boot is disabled via the following command: The rexec socket can be disabled with the following command:
$ sudo systemctl disable rexec.socket
The rexec socket can be masked with the following command:
$ sudo systemctl mask .socket

Rationale:

The telnet protocol uses unencrypted network communication, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network. The telnet protocol is also subject to man-in-the-middle attacks.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_service_telnet_disabled
Identifiers and References

References:  2.2.18, 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'telnet.service'
"$SYSTEMCTL_EXEC" disable 'telnet.service'
"$SYSTEMCTL_EXEC" mask 'telnet.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^telnet.socket'; then
    "$SYSTEMCTL_EXEC" stop 'telnet.socket'
    "$SYSTEMCTL_EXEC" disable 'telnet.socket'
    "$SYSTEMCTL_EXEC" mask 'telnet.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'telnet.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service telnet
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service telnet
      systemd:
        name: telnet.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"telnet.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_telnet_disabled

- name: Unit Socket Exists - telnet.socket
  command: systemctl list-unit-files telnet.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_telnet_disabled

- name: Disable socket telnet
  systemd:
    name: telnet.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"telnet.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_telnet_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_telnet

class disable_telnet {
  service {'telnet':
    enable => false,
    ensure => 'stopped',
  }
}
Group   Rlogin, Rsh, and Rexec   Group contains 4 rules

[ref]   The Berkeley r-commands are legacy services which allow cleartext remote access and have an insecure trust model.

Rule   Uninstall rsh-server Package   [ref]

The rsh-server package can be removed with the following command:

$ sudo yum erase rsh-server

Rationale:

The rsh-server service provides unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session and has very weak authentication. If a privileged user were to login using this service, the privileged user password could be compromised. The rsh-server package provides several obsolete and insecure network services. Removing it decreases the risk of those services' accidental (or intentional) activation.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_package_rsh-server_removed
Identifiers and References

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049



Complexity:low
Disruption:low
Strategy:disable

# CAUTION: This remediation script will remove rsh-server
#	   from the system, and may remove any packages
#	   that depend on rsh-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "rsh-server" ; then
    yum remove -y "rsh-server"
fi


Complexity:low
Disruption:low
Strategy:disable
- name: Ensure rsh-server is removed
  package:
    name: rsh-server
    state: absent
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - package_rsh-server_removed


Complexity:low
Disruption:low
Strategy:disable
include remove_rsh-server

class remove_rsh-server {
  package { 'rsh-server':
    ensure => 'purged',
  }
}


Complexity:low
Disruption:low
Strategy:disable

package --remove=rsh-server

Rule   Disable rlogin Service   [ref]

The rlogin service, which is available with the rsh-server package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set disable to yes in /etc/xinetd.d/rlogin. The rlogin socket can be disabled with the following command:

$ sudo systemctl disable rlogin.socket
The rlogin socket can be masked with the following command:
$ sudo systemctl mask .socket

Rationale:

The rlogin service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_service_rlogin_disabled
Identifiers and References

References:  2.2.17, 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rlogin.service'
"$SYSTEMCTL_EXEC" disable 'rlogin.service'
"$SYSTEMCTL_EXEC" mask 'rlogin.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^rlogin.socket'; then
    "$SYSTEMCTL_EXEC" stop 'rlogin.socket'
    "$SYSTEMCTL_EXEC" disable 'rlogin.socket'
    "$SYSTEMCTL_EXEC" mask 'rlogin.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rlogin.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rlogin
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service rlogin
      systemd:
        name: rlogin.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"rlogin.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_rlogin_disabled

- name: Unit Socket Exists - rlogin.socket
  command: systemctl list-unit-files rlogin.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_rlogin_disabled

- name: Disable socket rlogin
  systemd:
    name: rlogin.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"rlogin.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_rlogin_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_rlogin

class disable_rlogin {
  service {'rlogin':
    enable => false,
    ensure => 'stopped',
  }
}

Rule   Disable rexec Service   [ref]

The rexec service, which is available with the rsh-server package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set disable to yes in /etc/xinetd.d/rexec. The rexec socket can be disabled with the following command:

$ sudo systemctl disable rexec.socket
The rexec socket can be masked with the following command:
$ sudo systemctl mask .socket

Rationale:

The rexec service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_service_rexec_disabled
Identifiers and References

References:  2.2.17, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.13, 3.4.7, CCI-000068, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rexec.service'
"$SYSTEMCTL_EXEC" disable 'rexec.service'
"$SYSTEMCTL_EXEC" mask 'rexec.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^rexec.socket'; then
    "$SYSTEMCTL_EXEC" stop 'rexec.socket'
    "$SYSTEMCTL_EXEC" disable 'rexec.socket'
    "$SYSTEMCTL_EXEC" mask 'rexec.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rexec.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service rexec
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service rexec
      systemd:
        name: rexec.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"rexec.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_rexec_disabled

- name: Unit Socket Exists - rexec.socket
  command: systemctl list-unit-files rexec.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_rexec_disabled

- name: Disable socket rexec
  systemd:
    name: rexec.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"rexec.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.1.13
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - NIST-800-53-IA-5(1)(c)
    - disable_strategy
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - service_rexec_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_rexec

class disable_rexec {
  service {'rexec':
    enable => false,
    ensure => 'stopped',
  }
}

Rule   Remove Rsh Trust Files   [ref]

The files /etc/hosts.equiv and ~/.rhosts (in each user's home directory) list remote hosts and users that are trusted by the local system when using the rshd daemon. To remove these files, run the following command to delete them from any location:

$ sudo rm /etc/hosts.equiv
$ rm ~/.rhosts

Rationale:

This action is only meaningful if .rhosts support is permitted through PAM. Trust files are convenient, but when used in conjunction with the R-services, they can allow unauthenticated access to a system.

Severity: 
high
Rule ID:xccdf_org.ssgproject.content_rule_no_rsh_trust_files
Identifiers and References

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4



find /home -maxdepth 2 -type f -name .rhosts -exec rm -f '{}' \;

if [ -f /etc/hosts.equiv ]; then
	/bin/rm -f /etc/hosts.equiv
fi


Complexity:low
Disruption:low
Strategy:restrict
- block:

    - name: Detect shosts.equiv Files on the System
      find:
        paths: /
        recurse: true
        patterns: shosts.equiv
      check_mode: false
      register: shosts_equiv_locations

    - name: Remove Rsh Trust Files
      file:
        path: '{{ item.path }}'
        state: absent
      with_items: '{{ shosts_equiv_locations.files }}'
      when: shosts_equiv_locations
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - high_severity
    - low_complexity
    - low_disruption
    - no_reboot_needed
    - no_rsh_trust_files
    - restrict_strategy
Group   Xinetd   Group contains 2 rules

[ref]   The xinetd service acts as a dedicated listener for some network services (mostly, obsolete ones) and can be used to provide access controls and perform some logging. It has been largely obsoleted by other features, and it is not installed by default. The older Inetd service is not even available as part of Oracle Linux 8.

Rule   Uninstall xinetd Package   [ref]

The xinetd package can be removed with the following command:

$ sudo yum erase xinetd

Rationale:

Removing the xinetd package decreases the risk of the xinetd service's accidental (or intentional) activation.

Severity: 
low
Rule ID:xccdf_org.ssgproject.content_rule_package_xinetd_removed
Identifiers and References

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4



Complexity:low
Disruption:low
Strategy:disable

# CAUTION: This remediation script will remove xinetd
#	   from the system, and may remove any packages
#	   that depend on xinetd. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "xinetd" ; then
    yum remove -y "xinetd"
fi


Complexity:low
Disruption:low
Strategy:disable
- name: Ensure xinetd is removed
  package:
    name: xinetd
    state: absent
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - low_severity
    - no_reboot_needed
    - package_xinetd_removed


Complexity:low
Disruption:low
Strategy:disable
include remove_xinetd

class remove_xinetd {
  package { 'xinetd':
    ensure => 'purged',
  }
}


Complexity:low
Disruption:low
Strategy:disable

package --remove=xinetd

Rule   Disable xinetd Service   [ref]

The xinetd service can be disabled with the following command:

$ sudo systemctl disable xinetd.service
The xinetd service can be masked with the following command:
$ sudo systemctl mask xinetd.service

Rationale:

The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_service_xinetd_disabled
Identifiers and References

References:  2.1.7, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.4.7, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'xinetd.service'
"$SYSTEMCTL_EXEC" disable 'xinetd.service'
"$SYSTEMCTL_EXEC" mask 'xinetd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^xinetd.socket'; then
    "$SYSTEMCTL_EXEC" stop 'xinetd.socket'
    "$SYSTEMCTL_EXEC" disable 'xinetd.socket'
    "$SYSTEMCTL_EXEC" mask 'xinetd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'xinetd.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service xinetd
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service xinetd
      systemd:
        name: xinetd.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"xinetd.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_xinetd_disabled

- name: Unit Socket Exists - xinetd.socket
  command: systemctl list-unit-files xinetd.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_xinetd_disabled

- name: Disable socket xinetd
  systemd:
    name: xinetd.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"xinetd.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-171-3.4.7
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_xinetd_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_xinetd

class disable_xinetd {
  service {'xinetd':
    enable => false,
    ensure => 'stopped',
  }
}
Group   Chat/Messaging Services   Group contains 2 rules

[ref]   The talk software makes it possible for users to send and receive messages across systems through a terminal session.

Rule   Uninstall talk Package   [ref]

The talk package contains the client program for the Internet talk protocol, which allows the user to chat with other users on different systems. Talk is a communication program which copies lines from one terminal to the terminal of another user. The talk package can be removed with the following command:

$ sudo yum erase talk

Rationale:

The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the talk package decreases the risk of the accidental (or intentional) activation of talk client program.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_package_talk_removed
Identifiers and References

References:  2.3.3, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)



Complexity:low
Disruption:low
Strategy:disable

# CAUTION: This remediation script will remove talk
#	   from the system, and may remove any packages
#	   that depend on talk. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "talk" ; then
    yum remove -y "talk"
fi


Complexity:low
Disruption:low
Strategy:disable
- name: Ensure talk is removed
  package:
    name: talk
    state: absent
  tags:
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - package_talk_removed


Complexity:low
Disruption:low
Strategy:disable
include remove_talk

class remove_talk {
  package { 'talk':
    ensure => 'purged',
  }
}


Complexity:low
Disruption:low
Strategy:disable

package --remove=talk

Rule   Uninstall talk-server Package   [ref]

The talk-server package can be removed with the following command:

 $ sudo yum erase talk-server

Rationale:

The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the talk-server package decreases the risk of the accidental (or intentional) activation of talk services.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_package_talk-server_removed
Identifiers and References

References:  2.2.21, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)



Complexity:low
Disruption:low
Strategy:disable

# CAUTION: This remediation script will remove talk-server
#	   from the system, and may remove any packages
#	   that depend on talk-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "talk-server" ; then
    yum remove -y "talk-server"
fi


Complexity:low
Disruption:low
Strategy:disable
- name: Ensure talk-server is removed
  package:
    name: talk-server
    state: absent
  tags:
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - package_talk-server_removed


Complexity:low
Disruption:low
Strategy:disable
include remove_talk-server

class remove_talk-server {
  package { 'talk-server':
    ensure => 'purged',
  }
}


Complexity:low
Disruption:low
Strategy:disable

package --remove=talk-server
Group   Base Services   Group contains 1 rule

[ref]   This section addresses the base services that are installed on a Oracle Linux 8 default installation which are not covered in other sections. Some of these services listen on the network and should be treated with particular discretion. Other services are local system utilities that may or may not be extraneous. In general, system services should be disabled if not required.

Rule   Disable KDump Kernel Crash Analyzer (kdump)   [ref]

The kdump service provides a kernel crash dump analyzer. It uses the kexec system call to boot a secondary kernel ("capture" kernel) following a system crash, which can load information from the crashed kernel for analysis. The kdump service can be disabled with the following command:

$ sudo systemctl disable kdump.service
The kdump service can be masked with the following command:
$ sudo systemctl mask kdump.service

Rationale:

Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps consume a considerable amount of disk space and may result in denial of service by exhausting the available space on the target file system partition. Unless the system is used for kernel development or testing, there is little need to run the kdump service.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_service_kdump_disabled
Identifiers and References

References:  11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000366, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227



Complexity:low
Disruption:low
Strategy:disable


SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'kdump.service'
"$SYSTEMCTL_EXEC" disable 'kdump.service'
"$SYSTEMCTL_EXEC" mask 'kdump.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^kdump.socket'; then
    "$SYSTEMCTL_EXEC" stop 'kdump.socket'
    "$SYSTEMCTL_EXEC" disable 'kdump.socket'
    "$SYSTEMCTL_EXEC" mask 'kdump.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'kdump.service' || true


Complexity:low
Disruption:low
Strategy:disable
- name: Disable service kdump
  block:

    - name: Gather the service facts
      service_facts: null

    - name: Disable service kdump
      systemd:
        name: kdump.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when: '"kdump.service" in ansible_facts.services'
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_kdump_disabled

- name: Unit Socket Exists - kdump.socket
  command: systemctl list-unit-files kdump.socket
  args:
    warn: false
  register: socket_file_exists
  changed_when: false
  ignore_errors: true
  check_mode: false
  when: ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_kdump_disabled

- name: Disable socket kdump
  systemd:
    name: kdump.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
    - '"kdump.socket" in socket_file_exists.stdout_lines[1]'
    - ansible_virtualization_role != "guest" or ansible_virtualization_type != "docker"
  tags:
    - NIST-800-53-CM-6(a)
    - NIST-800-53-CM-7(a)
    - NIST-800-53-CM-7(b)
    - disable_strategy
    - low_complexity
    - low_disruption
    - medium_severity
    - no_reboot_needed
    - service_kdump_disabled


Complexity:low
Disruption:low
Strategy:enable
include disable_kdump

class disable_kdump {
  service {'kdump':
    enable => false,
    ensure => 'stopped',
  }
}



kdump --disable
Group   NFS and RPC   Group contains 1 group and 1 rule

[ref]   The Network File System is a popular distributed filesystem for the Unix environment, and is very widely deployed. This section discusses the circumstances under which it is possible to disable NFS and its dependencies, and then details steps which should be taken to secure NFS's configuration. This section is relevant to systems operating as NFS clients, as well as to those operating as NFS servers.

Group   Configure NFS Servers   Group contains 1 rule

[ref]   The steps in this section are appropriate for systems which operate as NFS servers.

Rule   Use Kerberos Security on All Exports   [ref]

Using Kerberos on all exported mounts prevents a malicious client or user from impersonating a system user. To cryptography authenticate users to the NFS server, add sec=krb5:krb5i:krb5p to each export in /etc/exports.

Rationale:

When an NFS server is configured to use AUTH_SYS a selected userid and groupid are used to handle requests from the remote user. The userid and groupid could mistakenly or maliciously be set incorrectly. The AUTH_GSS method of authentication uses certificates on the server and client systems to more securely authenticate the remote mount request.

Severity: 
medium
Rule ID:xccdf_org.ssgproject.content_rule_use_kerberos_security_all_exports
Identifiers and References

References:  1, 12, 14, 15, 16, 18, 3, 5, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.3, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.6.1.2, A.9.1.2, A.9.2.1, A.9.2.3, A.9.2.4, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), IA-2, IA-2(8), IA-2(9), AC-17(a), PR.AC-4, PR.AC-7, SRG-OS-000480-GPOS-00227

Red Hat and Red Hat Enterprise Linux are either registered trademarks or trademarks of Red Hat, Inc. in the United States and other countries. All other names are registered trademarks or trademarks of their respective companies.