Snort mailing list archives

Re: RE: 55808 window size [WAS: (no subject)]


From: Frank Knobbe <fknobbe () knobbeits com>
Date: 24 Jun 2003 18:21:55 -0500

On Tue, 2003-06-24 at 16:11, Coyle, Brian wrote:
As of this morning, I've now seen a couple of false positives from this rule.
Occasionally, a source with legit traffic[1] will start with a window size of 
55808.  Snort triggers on the 55808/SYN packet, but subsequent packets have 
a reduced window size.  The IP Seq. numbers will also vary as expected for 
regular traffic.


Other normal traffic has odd Window sizes as well (58400, 63999, 65217,
56940, 17207, 58204, 24616, etc). Why everyone is chasing 55808 is
beyond me. Yeah, it was/is the common thing with some of these scans,
but everyone is using that Window size _by_itself_ as some kind of
identifier (i.e. Snort rule). That's absurd. .... Oh well, don't get me
started on some of these so-called "security researchers" (or
market-droids).... sometimes I wonder if they not "find" exploits in
their own marketing department...

Joe Stewart said in an Incidents post "Probably someone's idea of a joke
on the infosec community." 

That "trojan" may not have been a joke, but the way some people made use
of the situation surely is a joke.

"Move on, nothing to see here." comes to mind...

Regards,
Frank

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