[Snort-devel] Snort Now Available

L0rd Ch0de1m0rt l0rdch0de1m0rt at ...2499...
Mon Nov 8 11:45:22 EST 2010


I am still experiencing HTTP stream reassembly issues when trying to
match across multiple fragmented packets with snort

Specifically, this happens on a HTTP POST where the headers are in a
different packet than the POST data. Consider the following rule you
can use along with scapy to reproduce if you want:

alert tcp any any -> $HOME_NET $HTTP_PORTS (msg:"Incoming German POST
to Batman"; flow:established,to_server; content:"POST"; http_method;
uricontent:"/batcave/"; uricontent:"unicorns4sourcefire"; content:"|0d
0a|Accept-Language: de"; nocase; http_header; content:!"|0d 0a 0d
0a|not4batman=true&"; content:!"\; batsecret=sesstoken4robin";
http_cookie; classtype:trojan-activity; sid:8008135; rev:17;)

It alerts (b/c all the URI and HTTP header stuffs match in the initial
packet) but it shouldn't alert b/c the HTTP POST data starts with
'not4batman=true&' (but the POST data is in a subsequent packet than
the one containing the headers).

Anyone else still having issues or have done more in-depth testing
with and the HTTP pre-processor?

-L0rd C.

On Tue, Nov 2, 2010 at 5:34 PM, Steven Sturges
<steve.sturges at ...402...> wrote:
> There was an issue in that HTTP inspect wasn't correctly handling
> raw vs. stream reassembled packets when looking at HTTP response
> data.  This fix is included in 2901 -- refer to ChangeLog (changes
> to hi_client.c/hi_server.c).
> As to the support of 2.8.6, with the release of 2.9.0, 2.8.6.x
> is no longer supported.  When there is a new "3 digit" release no
> further patches are made to the previous version of Snort.
> On 11/1/2010 1:05 PM, L0rd Ch0de1m0rt wrote:
>> Hello. Does this release fix the issue where the HTTP pre-processor
>> wasn't properly examining reassembled data across fragmented packets?
>> (I don't know the exact cause of the bug - maybe it was the other way
>> around and Stream5 wasn't properly doing the reassebly.)  It was
>> announced that there would be a patch for that issue, just want to see
>> if this is it.  If so, when can we expect the patch be
>> released? is still supported, right?
>> Thanks!
>> -L0rd C.
>> On Mon, Nov 1, 2010 at 11:45 AM, Snort Releases <snortreleases at ...835...> wrote:
>>> Snort is now available on snort.org, at
>>> http://www.snort.org/snort-downloads/.
>>> 2.9.0 RC & later packages are signed with a new PGP key
>>> (that is signed with the previous key).
>>> Snort addresses the following:
>>>  * Fixed maximum flowbits configuration parsing to specify the number
>>>    of bits in accordance with the Snort manual, rather than number of
>>>    bytes.  If you have 'config flowbits_size' in your snort.conf,
>>>    double check that it has the correct setting.
>>>  * Fixed a packet size issue with the IPQ and NFQ DAQs.
>>>  * Fixed issue with Stream5 overlap limit processing.
>>>  * Updated the version of LibPCRE bundled with the Windows installer.
>>>    This update fixes a bug that caused some PCRE matches to fail
>>>    on Windows.
>>> Please see the Release Notes and ChangeLog for more details.
>>> Please submit bugs, questions, and feedback to snort-beta at ...2780...
>>> Happy Snorting!
>>> The Snort Release Team
>>> ------------------------------------------------------------------------------
>>> Nokia and AT&T present the 2010 Calling All Innovators-North America contest
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>>> _______________________________________________
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