26 March, 2012

Updating to Snort 2.9.2 and Barnyard2

After fixing hardware problems that had my home network sensor out of commission for the better part of a year, I recently got the system inline again. Because the sensor had been down for so long, I was running a fairly old version of Snort, 2.9.0.3, along with barnyard 0.2.0. I decided the first thing I should do after updating the OS itself was update Snort and Barnyard.

I won't go through the process in detail since there are many resources online for installing and configuring Snort. The main thing I will point out is that you should always look in the docs/ directory for information on installing and upgrading. If you're updating from a previous version, pay particular attention to changes and new features. Another important thing to do is look closely at the snort.conf provided with a given version in etc/ since it will have a lot of information on defaults and configuration directives that may be required. These won't always be the same as previous versions. It's also important to update to the latest rule sets, check for new rules files, and do all the other normal tuning to make sure certain rules are turned off or on.

I had two main problems when I updated, one with Snort and one with Barnyard2. Since Snort is the main piece of the puzzle here, I updated it prior to Barnyard. After updating to Snort-2.9.2.1 and fixing the configuration, I was able to run Snort successfully using the options I normally had previously. However, as soon as I put the sensor back inline and Snort started processing packets, Snort would exit with an error.

Can't acquire (-1) - ipq_daq_acquire: ipq_read=-1 error Failed to receive netlink message!

A quick search revealed that I had to remove the ip_queue module. JJ Cummings on the #snort channel pointed out to me that NFQ is the more recent option than IPQ. I am using Slackware-current, so even though it is a maintained distribution it is also not surprising that I was using an older option. Slackware also did not have a couple of the required libraries to compile DAQ with support for NFQ, so I went to Slackbuilds.org to get the files allowing me to create Slackware packages for libnetfilter_queue and libnfnetlink.

Once I got the new packages installed, made sure the ip_queue module wasn't loaded, recompiled DAQ to support NFQ, and changed my Snort init to use --daq nfq, my inline Snort was working once again.

Next, I updated from Barnyard-0.2.0.

$ barnyard2 -V

  ______   -*> Barnyard2 <*-
 / ,,_  \  Version 2.1.10-beta2 (Build 266) TCL
 |o"  )~|  By Ian Firns (SecurixLive): http://www.securixlive.com/
 + '''' +  (C) Copyright 2008-2011 Ian Firns


Barnyard2 is needed to process Snort's newer output mode, unified2. My snort.conf changed from:

output log_unified: filename unified.log, limit 128

to:

output unified2: filename unified.log, limit 128

When I got Barnyard2 up and running, it was obviously not successfully processing the unified2 files from Snort. Barnyard2 kept repeating the following error as it tried to process the files.

WARNING: No function defined to read header.

I found a thread on the snort-users list that indicated Barnyard2 was getting a file type it wasn't expecting, which made sense considering the warning message. This issue gave me more problems than it should have and I eventually realized it was because of an error in my barnyard.conf file. The input is supposed to read "input unified2" but I had somehow managed to include a colon after "input". Once I fixed that line, Barnyard2 started working, with alerts being properly processed and showing up in Sguil once again.

The next update will be to go from Sguil-0.7.0 to Sguil-0.8.0.

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