Snort mailing list archives

Re: Quick uricontent question


From: James Lay <jlay () slave-tothe-box net>
Date: Wed, 19 Sep 2012 15:33:55 -0600

On 2012-09-19 15:26, Joel Esler wrote:
James, in this case %u and such are variable fields.  (The theme is
digits and the siteID is also digits if it's the first report)

So, what you'd want is something like this:

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS
(msg:"MALWARE-CNC Win.Trojan.Zeroaccess variant outbound
communication"; flow:to_server,established;
content:"/counter.img?theme="; nocase; http_uri; content:"&digits=";
nocase; http_uri; distance:0; content:"&siteId="; nocase; http_uri;
distance:0; pcre:"/theme\=\d+\&digits\=/Ui"; metadata:policy
balanced-ips drop, policy security-ips drop, service http;

reference:url,www.sophos.com/en-us/why-sophos/our-people/technical-papers/zeroaccess-botnet.aspx;
classtype:trojan-activity;)

Now, I haven't tested this against any pcaps or samples, I simply
wrote this freehand by looking at the pdf you linked there.

I'll do some testing and we'll try and get this (or something very
similar) out.

--
Joel Esler
Senior Research Engineer, VRT
OpenSource Community Manager
Sourcefire


Thanks Joel...that was quick work!

James


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