Re: Snort and buffering of packets

[Joel Esler <jesler () sourcefire com>]

Dear Knut,

Thanks for your email.  I believe you will find what you are looking for here: http://manual.snort.org/node470.html

Use a flowbit to set a flowbit on the JPEG header, then check that flowbit in a separate rule.

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

On Jan 18, 2013, at 7:58 AM, Knut Borg <knutborg () gmail com> wrote:

> Hey, I have a question about buffering of packets.
>
> What I want to do is that I want Snort to check for JPEG files in the network stream, which is easy because I ask 
> Snort to look for the JPEG header. Then after Snort have detected a JPEG-file, I want Snort to store the JPEG file in 
> a buffer (i.e. not write it to disk, only store it in RAM). Then I'm going to check the JPEG-file for bit patterns 
> while Snort still have the file stored in memory. If I can't find my own watermarks Snort will send the packet as 
> normal, if not I want Snort to drop the packet. The reason why I don't want to store the JPEG file to a hard drive is 
> for efficiency purposes. 
>
> I'm currently experimenting with the idea and I'm wondering if it is possible to pull off? I heard something about 
> Snort being able to quarantine packets, but I'm not sure if I would be able to access those packets if they are 
> quarantined.
>
>
>
> Thanks in advance
> Knut
>
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