Re: Win32/64 Napolar sig

[Nick Randolph <drandolph () sourcefire com>]

This is what we ended up with
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"MALWARE-CNC
Win.Trojan.Napolar outbound connection attempt"; flow:to_server,
established; content:"POST"; http_method; content:"v="; http_client_body;
content:"|26|u="; within:3; distance:3; http_client_body; content:"|26|c=";
distance:0; http_client_body; content:"|26|s={"; distance:0;
http_client_body; content:"}|26|w="; within:4; distance:36;
http_client_body; metadata:impact_flag red, policy balanced-ips drop,
policy security-ips drop, ruleset community, service http; reference:url,
www.virustotal.com/en/file/463d39dcbf19b5c4c9e314e5ce77bf8a51848b8c7d64e4f0a6656b9d28941e2e/analysis/;
classtype:trojan-activity; sid:28079; rev:1;)

Another contributor submitted this as well

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"MALWARE-CNC
Win.Napolar trojan data theft"; flow:to_server,established;
content:".exe&h="; fast_pattern:only; http_client_body; content:"p=";
depth:2; http_client_body; metadata:impact_flag red, policy security-ips
drop, ruleset community, service http; reference:url,
www.virustotal.com/en/file/12781be5908ecc3dbf4a459e4cbc7bedb654b50236f7a961e85f3af5e2275ddf/analysis/;
classtype:trojan-activity; sid:28080; rev:1;)


On Wed, Sep 25, 2013 at 5:32 PM, James Lay <jlay () slave-tothe-box net> wrote:

> On 2013-09-25 15:24, James Lay wrote:
> > On 2013-09-25 14:21, Nick Randolph wrote:
> > > I would bet that the USER_NAME and COMP_NAME are variable depending
> > > on
> > > the victim. Avast might have removed them to hide some internal
> > > data.
> > > They did include some hashes so Ill run those through our sandbox
> > > and
> > > let you know what I see.
> > >
> > > On Wed, Sep 25, 2013 at 3:30 PM, James Lay <jlay () slave-tothe-box net
> > > [7]> wrote:
> > >
> > > > First attempt...hope it doesnt stink :)
> > > >
> > > > alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS
> > > > (msg:"MALWARE-CNC
> > > > W32/64.Napolar initial POST"; flow:to_server, established;
> > > > file_data;
> > > > content:"|26|u=USER_NAME|26|c=COMP_NAME|26|s="; fast_pattern:only;
> > > > metadata:policy balanced-ips drop, policy security-ips drop,
> > > > service
> > > > http, ruleset community;
> > >
> > >
> > > reference:url,
> blog.avast.com/2013/09/25/win3264napolar-new-trojan-shines-on-the-cyber-crime-scene/
> > > > [1];
> > > > classtype:trojan-activity; sid:10000099; rev:1;)
> > > >
> > > > James
> >
> > Yep...variables:
> http://www.welivesecurity.com/2013/09/25/win32napolar-a-new-bot-on-the-block/
> > Darn.
> >
> > James
>
> Meh:
>
> alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"MALWARE-CNC
> W32/64.Napolar initial POST"; flow:to_server, established; file_data;
> content:"POST"; http_method; content:"v="; content:"|26|u=";
> content:"|26|c="; content:"|26|s="; metadata:policy balanced-ips drop,
> policy security-ips drop, service http, ruleset community;
> reference:url,
> blog.avast.com/2013/09/25/win3264napolar-new-trojan-shines-on-the-cyber-crime-scene/
> ;
> classtype:trojan-activity; sid:10000099; rev:2;)
>
> This is probably cheesy....bet the proper way would be to lookup max
> username and machine name and allowed characters for winders and PCRE it
> up...but to be real honest I'm just not in the mood for pcre today ;)
>
> James
>
>
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-- 

Nick Randolph
Research Engineer
Sourcefire, Inc.
nrandolph () sourcefire com
Sourcefire.com <http://www.sourcefire.com/>

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Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from 
the latest Intel processors and coprocessors. See abstracts and register >
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