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Re: HTTP Inspect and packet reassembly
From: Joel Esler <jesler () sourcefire com>
Date: Thu, 28 Oct 2010 20:51:03 -0400

Excellent, thank you all for the reports.  Does anyone have a pcap they can provide with this traffic in it so we can 
diagnose and fix it?


Sent from my iPhone

On Oct 28, 2010, at 8:26 PM, Eoin Miller <eoin.miller () trojanedbinaries com> wrote:

We have seen this as well, I wrote up a blog post about it.

http://trojanedbinaries.com/blog/?p=217

Seems to only create the buffers based off of the frame and not the stream.

On Oct 29, 2010, at 1:03 AM, matan monitz <mmonitz () gmail com> wrote:

we  also came across this
specifically on http post signatures
a large enough request (big viewstate or a large post payload) using more then one packet will end in the second 
packet not getting into http_client_body buffer 




On Thu, Oct 28, 2010 at 4:09 PM, Joel Esler <jesler () sourcefire com> wrote:
Can you provide us with a pcap dump of the traffic?

Joel

On Oct 28, 2010, at 9:40 AM, L0rd Ch0de1m0rt wrote:

Hello.  I am investigating a situation where TCP streams are being
fragmented quite small at the IP layer for some reason (load
balancer?) and it seems to be causing problems for some of my rules
that leverage HTTP Inspect.  From the manual I read this:

"The current version of HTTP Inspect only handles stateless
processing. This means that HTTP Inspect looks for HTTP
fields on a packet-by-packet basis, and will be fooled if packets are
not reassembled. This works fine when there is
another module handling the reassembly, but there are limitations in
analyzing the protocol. Future versions will have
a stateful processing mode which will hook into various reassembly modules."

OK, so HTTP Inspect is stateless and doesn't reassemble packets.  But
then there is the sentence, "This works fine when there is another
module handling the reassembly, but there are limitations in analyzing
the protocol."  So my question is, if I also have Stream5 enabled for
TCP, is that a sufficient "another module" or are there still
"limitations" with the HTTP protocol?

Specifically, I have problems with rules that use uricontent and
content and need to match across more than one packet.

Thanks!

-L0rd C.

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------------------------------------------------------------------------------
Nokia and AT&T present the 2010 Calling All Innovators-North America contest
Create new apps & games for the Nokia N8 for consumers in  U.S. and Canada
$10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing
Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store
http://p.sf.net/sfu/nokia-dev2dev
_______________________________________________
Snort-devel mailing list
Snort-devel () lists sourceforge net
https://lists.sourceforge.net/lists/listinfo/snort-devel

------------------------------------------------------------------------------
Nokia and AT&T present the 2010 Calling All Innovators-North America contest
Create new apps & games for the Nokia N8 for consumers in  U.S. and Canada
$10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing
Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store 
http://p.sf.net/sfu/nokia-dev2dev
_______________________________________________
Snort-devel mailing list
Snort-devel () lists sourceforge net
https://lists.sourceforge.net/lists/listinfo/snort-devel
------------------------------------------------------------------------------
Nokia and AT&T present the 2010 Calling All Innovators-North America contest
Create new apps & games for the Nokia N8 for consumers in  U.S. and Canada
$10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing
Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store 
http://p.sf.net/sfu/nokia-dev2dev
_______________________________________________
Snort-devel mailing list
Snort-devel () lists sourceforge net
https://lists.sourceforge.net/lists/listinfo/snort-devel

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