Snort mailing list archives

Re: Incorrect payload on acid alerts


From: "M. Shirk" <shirkdog_linux () hotmail com>
Date: Wed, 10 Nov 2004 08:43:40 -0500

I am able to receive multiple HTTP connections as single alerts. The *bot variants that blow up alot of ports and send the webdav search overflow generate about 12 separate alerts for each full length packet to tcp port 80. I will get the apparent overflow packets in order.

(Start of packets, and these are followed by alerts with just the hex data)
53 45 41 52 43 48 20 2F 90 02 B1 02 B1 02 B1 02  SEARCH /........
B1 02 B1 02 B1 02 B1 02 B1 02 B1 02 B1 02 B1 02  ................
B1 02 B1 02 B1 02 B1 02 B1 02 B1 02 B1 02 B1 02  ................
B1 02 B1 02 B1 02 B1 02 B1 02 B1 02 B1 02 B1 02  ...............

53 45 41 52 43 48 20 2F 90 C9 C9 C9 C9 C9 C9 C9  SEARCH /........
C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9  ................
C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9  ................
C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9 C9  ................


Shirkdog


From: Jason Haar <Jason.Haar () trimble co nz>
To: snort-users () lists sourceforge net
Subject: Re: [Snort-users] Incorrect payload on acid alerts
Date: Wed, 10 Nov 2004 15:09:24 +1300

Joshua Berry wrote:

Several times I have seen a similar issue for HTTP sessions where
multiple HTTP connections are shown for own alert.  It appears that
several sessions had been combined into a single snort alert and many of
these sessions did not match any of the signatures.



I hate to do a "me too" - but, me too.

I was sitting on it until I could come up with something more substantial to help find the problem, but I've seen snort trigger a "EXPLOIT ssh CRC32 overflow NOOP" between two hosts I control, and yet the packet captured by snort was actually HTTP headers bunged onto the end of some binary data.

It wasn't SSH data, it wasn't HTTP data, it was...? Packet length was 2630 - which makes me think there's still a bug in how snort aggregates packets together into flows

This was snort-2.2.0 under Fedora Core 2

Jason

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