Snort mailing list archives
Re: Alerts not Detected during Import?
From: Erek Adams <erek () snort org>
Date: Thu, 26 Jun 2003 12:30:58 -0400 (EDT)
On Thu, 26 Jun 2003, Dusty Hall wrote:
We are experiencing a problem with Snort not reporting Alerts that we have in our rules files. Here's some background: We copy our Snort tcpdump logs from our sniffer to our MySQL/ACID system and then import the tcpdump logs into ACID/MySQL. From the looks of our alert files the Specific alerts were detected by our sniffer but not by Snort on our DB box. So what I'm trying to ask is, does the tcpdump log files from our sniffer box have all detected alerts in tcpdump format that were sniffed on the wire? Is there enough information from the tcpdump files from our sniffer to process again and pull out the same alerts? Here's the steps we use: (Yes we have identicial rules on both systems and both have the same version of Snort.)
[...good info snipped...] Yes, there is a reason. It has to do with stream4. stream4 looks at all the packets on the net and tracks state and streams. snort1 has the view of the network, while snort2 only has the tcpdump file generated by snort1. The tcpdump file _only_ has the packets that triggered the alert--Not the previous ones, which is what stream4 uses to track things. So snort2 won't alert on any rule that has to do with 'flow'. A quick bit of greping shows: [erek@foofus]/usr/local/build/cvs/snort/rules>wc -l *|tail -1 3171 total [erek@foofus]/usr/local/build/cvs/snort/rules>grep -i flow *.rules | wc -l 1511 So there's roughly half the rules that won't fire on snort2. It's not really a 'bug', it's just more a 'consequence'. Hope that helps! ----- Erek Adams "When things get weird, the weird turn pro." H.S. Thompson ------------------------------------------------------- This SF.Net email is sponsored by: INetU Attention Web Developers & Consultants: Become An INetU Hosting Partner. Refer Dedicated Servers. We Manage Them. You Get 10% Monthly Commission! INetU Dedicated Managed Hosting http://www.inetu.net/partner/index.php _______________________________________________ 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:
- Alerts not Detected during Import? Dusty Hall (Jun 26)
- Re: Alerts not Detected during Import? Erek Adams (Jun 26)
- <Possible follow-ups>
- Re: Alerts not Detected during Import? Dusty Hall (Jun 26)
- Re: Alerts not Detected during Import? Erek Adams (Jun 26)
- Re: Alerts not Detected during Import? Chris Green (Jun 26)