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Re: Namihno Trojan
From: Joel Esler <jesler () sourcefire com>
Date: Mon, 20 May 2013 11:28:19 -0400

No, thank you for contributing!

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

On May 20, 2013, at 11:05 AM, Paul Bottomley <Paul.Bottomley () betfair com> wrote:

Nicely optimised, thanks Joel!
 
 
From: Joel Esler [mailto:jesler () sourcefire com] 
Sent: 20 May 2013 16:01
To: Paul Bottomley
Cc: snort-sigs () lists sourceforge net
Subject: Re: [Snort-sigs] Namihno Trojan
 
Paul,
 
Thanks.  I committed it like this:
 
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"MALWARE-CNC Namihno Trojan CnC Request"; 
flow:to_server,established; content:"/windows/update/search?hl="; http_uri; content:"&q="; distance:0; http_uri; 
content:"&meta="; distance:0; http_uri; content:"&id="; distance:0; http_uri; metadata:policy security-ips drop, 
ruleset community, service http; classtype:trojan-activity; sid:26695; rev:2;)
 
Since there really isn't a need for the pcre, I just used the content matches and made them relative to each other.   
This should work much faster.
 
Thanks!
 
--
Joel Esler
Senior Research Engineer, VRT
OpenSource Community Manager
Sourcefire
 
 
On May 20, 2013, at 10:17 AM, Paul Bottomley <Paul.Bottomley () betfair com> wrote:


Sorry don't have a reference for this (Intel was received through our TI provider).
 
"The following URI is hard-coded into the sample and used to construct the HTTP C2 request:
/windows/update/search?hl=%s&q=%s&meta=%s&id=%s
URI parameters within the HTTP request contain the Base64-encoded hostname and IP address of the victim's computer."
 
I've assumed all occurrences of %s are Base64 but I can't get the rule to fire when a '+' occurs within the character 
class (using \x2b)- not sure why? I’ve also probably escaped some characters that don’t need escaping.
 
Anyway, here is the rule I've created. Feel free to modify if you like.
 
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"[C2] Namihno Trojan CnC Request"; 
flow:established,to_server; content:"/windows/update/search?hl="; fast_pattern:only; http_uri; 
pcre:"/\/windows\/update\/search\?hl\=[a-z0-9\x2b\x2f\x3d]+\&q\=[a-z0-9\x2b\x2f\x3d]+\&meta\=[a-z0-9\x2b\x2f\x3d]+\&id\=[a-z0-9\x2b\x2f\x3d]+$/Ui";
 classtype:trojan-activity; sid:xxxxx; rev:1;)
 
Thanks

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security visibility with the essential security capabilities. Easily and
efficiently configure, manage, and operate all of your security controls
from a single console and one unified framework. Download a free trial.
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Snort-sigs () lists sourceforge net
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Please visit http://blog.snort.org for the latest news about Snort!
 

________________________________________________________________________
In order to protect our email recipients, Betfair Group use SkyScan from 
MessageLabs to scan all Incoming and Outgoing mail for viruses.

________________________________________________________________________

------------------------------------------------------------------------------
AlienVault Unified Security Management (USM) platform delivers complete
security visibility with the essential security capabilities. Easily and
efficiently configure, manage, and operate all of your security controls
from a single console and one unified framework. Download a free trial.
http://p.sf.net/sfu/alienvault_d2d
_______________________________________________
Snort-sigs mailing list
Snort-sigs () lists sourceforge net
https://lists.sourceforge.net/lists/listinfo/snort-sigs
http://www.snort.org


Please visit http://blog.snort.org for the latest news about Snort!

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