Snort mailing list archives
Re: HOWTO on managing IDS rules?
From: Chris Green <cmg () uab edu>
Date: Tue, 25 Sep 2001 21:11:16 -0500
Jason Haar <Jason.Haar () trimble co nz> writes:
I've been running snort for some time now, and am trying to formalize how we handle signature management. As we all know, False Alerts are not our friends. I'm trying to generate a more appropriate way of dealing with signatures, and as always, would like to hear from others if this is a Good Idea... So, we have a DMZ. We get our obligatory 10,000 CodeRed/Nimda alerts per week from Snort. We are not interested in these alerts, as our servers are patched and/or Apache. OTOH, we don't want to stop detecting CodeRed/Nimda as one day some git (i.e. me :-) may put an unsecured M$ IIS server in the DMZ without thinking. So what we really want is to: 1> stop reporting on attack types we know ourselves to be immune to, to reduce the amount of logs that need checking.
The right way to do this IMO is in post processing so you still get the alert but it can be used later. The number of times I saw a machine "safe" from IIS patches and then they apply a Service Pack scenarios are what gives me this opinion. Perhaps move it into a "signs of a successful attack" alert too. I do this with lots of odd outgoing rules.
2> document that this attack (from Internet to DMZ) is no longer being looked for.
3> start reporting on the same attack FROM DMZ TO INTERNET. This way we should catch any erroneously installed machines at a later date.
This is about what I've said above. I just move these types of alerts out of the 'critical' bag.
Sounds like a plan? Any other ways people are dealing with this "information overload"?
Snort Snarf's style summaries can be be good for handling this and you'll find yourself ignoring certain types of alerts. If you've got the pager type setup, it's definately 'take this attack out of critical section' -- Chris Green <cmg () uab edu> Fame may be fleeting but obscurity is forever. _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- HOWTO on managing IDS rules? Jason Haar (Sep 25)
- Re: HOWTO on managing IDS rules? Chris Green (Sep 25)
- Re: HOWTO on managing IDS rules? Phil Wood (Sep 26)
- Re: HOWTO on managing IDS rules? Chris Green (Sep 25)