[Snort-users] welchia rule

Schmehl, Paul L pauls at ...6838...
Tue Nov 4 14:08:10 EST 2003


> -----Original Message-----
> From: Leonard Miller [mailto:Leonard.Miller at ...7710...] 
> Sent: Tuesday, November 04, 2003 2:39 PM
> To: snort-users at lists.sourceforge.net; dortega at ...10460...; 
> Leonard Miller; Schmehl, Paul L
> Subject: RE: [Snort-users] welchia rule
> 
> Would it matter if the payload was aaaaaaaaaaaaaaaaaaaa
> and not aaaa aaaa aaaa aaaa 
> The reason I ask is that I saw on arachNIDS that the rule was 
> a little different and picked up as CyberKit 2.2 Windows

Not really.  It's just convention to separate them that way.  It makes
it easier to read the hex when it varies.

BTW, I just upgraded a snort box to 2.0.2 and edited the rule to include
thresholding.  It's working great and appears to have eliminated all
"false positives", AFAICT.

Here it is:

# 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 aaaa 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 limit, track by_src, count 500, seconds 60;
classtype:trojan-activity;\
 sid: 10000008; rev: 2;)

Paul Schmehl (pauls at ...6838...)
Adjunct Information Security Officer
The University of Texas at Dallas
AVIEN Founding Member
http://www.utdallas.edu/~pauls/ 




More information about the Snort-users mailing list