Saturday, May 19, 2007

I Created some scripts for Snort

I've created (well, modified) a Snort initialization, restart, and shutdown script for Slackware and OpenBSD. They are linked below.

The OpenBSD script works solidly.

The Slackware script works sporadically and I've no idea how to debug it (although I haven't tried 'strace' yet). It appears to work manually every time, but when run as a cron job, it's sometimes, seemingly randomly, doesn't restart. The cron job runs every hours but because it sometimes doesn't start, I now have holes in my website's IDS coverage.

Note that I didn't HAVE to create start/stop scripts for Snort, as I could've started Snort by utilizing the rc.local file, but I'd have still had to manually kill the Snort process whenever I wanted to stop Snort. Having an init script do this is much cleaner.

The fact that I've gotten it working on the OpenBSD machine hints that I've a minor issue with the Slackware script that I have yet to account for, but its frustrating me, so I'll throw it online to see if someone can help with debugging. Yeah, I'd searched for help via Google but didn't see much of Snort init scripts for Slackware (although I may find something if I look at any scripts for other distributions).

I also got Snortalog to process my Snort raw logs into a statistical report, although I had to import 6.2MB of flat files to my FreeBSD box (which Snortalog is installed on), then have Snortalog crunch that data into a HUGE (3.9MB) HTML file! Needless to say, that HTML file takes almost 5 minutes to load into a browser. I've got to filter the logs and only have it crunch certain dates to make the file less bulky.

Snortalog definitely highlights that I could do some tuning, as it shows a very high amount of MS-SQL worm attempts (MS Blaster) hitting my server, amongst other things. This is a good tool that I'd previously used (and had forgotten) at a prior place of employment. It would be nice if I could figure out how to get it to crunch my IPF FW logs.

Another oldie but goddie is SnortSnarf. It is a perl script, as is Snortalog, that parses Snort files (the alert file and the payload files) into readable HTML pages, which is a bit better at searching via command-line. It is not as handy as ACID/BASE is, though, but has lower overhead. Sadly, SnortSnarf's home page is gone, but I've linked's archive.


I've found my 'error'. What happened was that I had line 34 commented out and line 35 uncommented. Line 35 is specifically for usage with OpenBSD. Line 34 is specifically for Slackware. I rectified this by uncommenting line 34 and commenting line 35. I'll also put commentary explaining this. Consider this issue solved!

Edited 8/30/2007:

Revised Script that works! *yes, click here*
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