Snort mailing list archives
RE: Filtering alerts
From: "Richard Brackett" <rbrackett () securityvolition com>
Date: Tue, 23 Sep 2003 09:42:48 -0400
I understand what you're saying, but what about a rule I'm interested in like the IIS Code Red rule. I know that all my current servers are patched against it so the alerts I get are just noise. I'm loath to disable the rule though because I never know when someone might put up an unpatched IIS box and get it infected. So, I'd like to be able to say "Don't alert when you see this attack to these addresses, but please alert to any other address." The only way to do it with Snort seems to be to use pass rules, which are supposed to take more CPU cycles to process. The BPF rules don't help me with individual SID's, just IP's and protocols. Is there an output processing system that will filter alerts before sending them to mysql for ACID to look at? -----Original Message----- From: Erek Adams [mailto:erek () snort org] Sent: Tuesday, September 23, 2003 6:52 AM To: Richard Brackett Cc: snort-users () lists sourceforge net Subject: RE: [Snort-users] Filtering alerts On Mon, 22 Sep 2003, Richard Brackett wrote:
Yes, I saw that. That's why I upgraded to 2.0.2. :-) It doesn't help me with "noise" though. For example, I don't care
about
the various IIS related signatures that fire against my Citrix
servers.
They aren't vulnerable to those attacks. I don't want to turn the rule off though, because I have IIS servers and I never know when some yutz is going to put a new one up without patches.
It's called "rule tuning". Offhand, I'd guess that you're running the standard default ruleset. If you are that's your trouble. Those default rules aren't setup to be used in a "real world" situation due to how noisy they are. They are more suited for some sort of small net with a low amount of traffic. If using that, you simply need to go over each rule and decide how important it is for your network. Disable rules as needed, and fine tune others. You can also use BPF filters which saves you on processing overhead. Check FAQ 3.9 [0]. Cheers! ----- Erek Adams "When things get weird, the weird turn pro." H.S. Thompson [0] http://www.snort.org/docs/FAQ.txt ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ 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:
- Filtering alerts Richard Brackett (Sep 22)
- Re: Filtering alerts Geoff (Sep 22)
- <Possible follow-ups>
- RE: Filtering alerts Richard Brackett (Sep 22)
- RE: Filtering alerts Erek Adams (Sep 23)
- RE: Filtering alerts Richard Brackett (Sep 23)
- RE: Filtering alerts Erek Adams (Sep 23)
- RE: Filtering alerts Richard Brackett (Sep 23)
- RE: Filtering alerts Marc Quibell (Sep 23)