Indexed Logging Output with ElasticSearch

Intro

Bro’s default ASCII log format is not exactly the most efficient way for searching large volumes of data. ElasticSearch is a new data storage technology for dealing with tons of data. It’s also a search engine built on top of Apache’s Lucene project. It scales very well, both for distributed indexing and distributed searching.

Warning

This writer plugin is still in testing and is not yet recommended for production use! The approach to how logs are handled in the plugin is “fire and forget” at this time, there is no error handling if the server fails to respond successfully to the insertion request.

Installing ElasticSearch

Download the latest version from: http://www.elasticsearch.org/download/. Once extracted, start ElasticSearch with:

# ./bin/elasticsearch

For more detailed information, refer to the ElasticSearch installation documentation: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/setup.html

Installing the ElasticSearch Plugin

First, ensure that you have libcurl (headers and library) installed. Then the following will compile and install the plugin alongside Bro:

# ./configure && make && make install

See the output of ./configure --help for additional options if it can’t find any of the prerequisites.

If everything built and installed correctly, you should see this:

# bro -N Bro::ElasticSearch
Bro::ElasticSearch - ElasticSearch log writer (dynamic, version 1.0)

Activating ElasticSearch

The easiest way to enable ElasticSearch output is to load the plugin’s logs-to-elasticsearch.bro script. If you are using BroControl, the following line in local.bro will enable it:

@load Bro/ElasticSearch/logs-to-elasticsearch.bro

With that, Bro will now write most of its logs into ElasticSearch in addition to maintaining the Ascii logs like it would do by default. That script has some tunable options for choosing which logs to send to ElasticSearch, refer to the autogenerated script documentation for those options.

There is an interface being written specifically to integrate with the data that Bro outputs into ElasticSearch named Brownian. It can be found here:

https://github.com/grigorescu/Brownian

Tuning

A common problem encountered with ElasticSearch is too many files being held open. The ElasticSearch documentation has some suggestions on this and other issues.

TODO

Lots.

  • Perform multicast discovery for server.
  • Better error detection.
  • Better defaults (don’t index loaded-plugins, for instance).
Copyright 2013, The Bro Project. Last updated on July 19, 2016. Created using Sphinx 1.4.4.