[Snort-users] Re: [Snort-sigs] Slapper signature ??

Jukka Juslin jtjuslin at ...7943...
Thu Jan 9 10:40:23 EST 2003


On Tue, 7 Jan 2003, Ashley Thomas wrote:

->Hi all,
->
->Snort signature for detecting slapper worm's communication messages is -
->
->alert udp $EXTERNAL_NET 2002 -> $HTTP_SERVERS 2002 (msg:"MISC slapper
->worm admin traffic";
->content:"|0000 4500 0045 0000 4000|"; offset:0; depth:10;
->classtype:trojan-activity;
->reference:url,www.cert.org/advisories/CA-2002-27.html;
->reference:url,isc.incidents.org/analysis.html?id=167; sid:1889; rev:3;)
->
->Should we be matching for content: "|0000 4500 0045 0000 4000|";
->or
->content: "|4500 0045 0000 4000|";
->
->I could not understand why the 0000 is there at the starting.

I launched a test slapper attack and I was able detect it fine with
content: "|4500 0045 0000 4000|". Therefore I think the 0000 is not
needed.

By the way, why are you so concerned with such an old attack? I think
Microsoft SQL servers etc are much more targeted now (according to
incidents.org). I am a bit concerned that I don't see much more new snort
filters coming up for new vulnerabilities?

Maybe I just have to write the filters I need by myself to accomplish what
I want.

Jukka Juslin
M.Sc. (CS)
European Organization for Nuclear Research





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