🐐 Capra

Capra is a powerful Intrusion Detection System.

$ gem install capra

To start, we will create a base Caprafile using the init sub-command:

$ capra init

By default, it will find your default network interface, which will work in most cases. You can also specify the interface to use:

$ capra init --interface eth0

A default Caprafile looks like this:

#!/usr/bin/env ruby

interface "eth0"

# your rules go here

You can convert snort rules to Caprafile syntax:

$ capra convert 'alert tcp any any -> any 21 (msg:"ftp")'
rule 'TCP' do |packet|
        next unless packet.tcp.dport == 21
        alert "ftp"
end

You can append the converted snort rule output to the Caprafile like so:

$ capra convert 'alert tcp any any -> any 21 (msg:"ftp")' >> Caprafile

You can also covert snort rules from a given file:

$ capra convert snort_rules.txt
...

Starting the engine is a simple as:

$ capra start
...

After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/picatz/capra. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the Capra project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.