Snort mailing list archives
Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts..
From: Jim Brown <jpb () sixshooter v6 thrupoint net>
Date: Sat, 3 Jan 2004 19:10:46 -0500
* Paul Schmehl <pauls () utdallas edu> [2004-01-01 01:11]:
----- Original Message ----- From: "Jeff Kell" <jeff-kell () utc edu> To: "Brice B" <nesta () iceburg net> Cc: <chris.northrop () po state ct us>; <snort-users () lists sourceforge net> Sent: Wednesday, December 31, 2003 8:38 PM Subject: Re: [Snort-users] SUMMARY, CyberKit 2.2 Ping, its driven me Nuts..Can anyone verify the [non]existance of a difference between the Cyberkit and Nachi pings? Not having Cyberkit myself, I can only address Nachi. The frame is 106 bytes on the wire, 92 bytes in the IP packet, and 64 bytes of 0xaa in the ICMP data payload. If Cyberkit is anything but 64 bytes of 0xaa payload, perhaps a new, Nachi-specific rule is called for.Here's the rule I wrote, which I've posted to the list several times. It uses thresholding and triggers one alert per minute. If you get *any* alerts with this rule, I *guarantee* you it's a machine infected with Nachi or a new variant of Nachi. # This rule is for tracking Nachi infections alert icmp $HOME_NET any -> any any (msg: "ALERT!!! NACHI Infection!!"; content: "|aaaa aaaa aaaa aaaa aaaa aaaa aaaa aa aa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa aaaa|"; dsize:64; itype: 8; icode: 0; threshold: type both, track by_src, count 1000, seconds 60; classtype:trojan-activity; si d: 10000008; rev: 4;) The usual rules apply. This must be either all on one line or properly "escaped", so you'll have to fix it if you copy and paste. Note that this rule *only* triggers for internal infections, *not* for infected machines on $EXTERNAL_NET, so you need to edit it appropriately for what you are looking for on your network. I.e. change $HOME_NET to any if you want to catch *all* infections or $EXTERNAL_NET if you want to catch *incoming* infections. Paul Schmehl (pauls () utdallas edu) Adjunct Information Security Officer University of Texas at Dallas http://www.utdallas.edu/ir/
I'm curious about your threshold count of 1000 per minute. I've only seen activity on the order of 12-15 messages/second on a 'blast' with several seconds between blasts. This wouldn't get me to 1000 in one minute for most minutes. What are your stats? Are you seeing more than 15 messages/second? Best Regards, jpb === ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ 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:
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Brice B (Dec 31)
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Jeff Kell (Dec 31)
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Jeff Kell (Dec 31)
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Paul Schmehl (Dec 31)
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Jim Brown (Jan 03)
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Paul Schmehl (Jan 03)
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Jeff Kell (Dec 31)
- RE: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Chris N (Jan 02)
- <Possible follow-ups>
- Re: SUMMARY, CyberKit 2.2 Ping, its driven me Nuts.. Simon Smith (Dec 31)