Re: Blocking WMF Files via Squid

["Gyenyami InvestinLoss" <d69frk () hotmail com>]

Yes it is a great Idea, there are also IDS flags at Bleeding Snort that will 
also help at the perimeter. Keep in mind also the UN OF patch thats out 
there not to beat a dead horse though.


Jasun Tate CEH,NET+
Network Security Engineer ICW


> From: "Robert J. Stull" <Stull_Robert_J () cat com>
> To: "Gaddis, Jeremy L." <jeremy () linuxwiz net>
> CC: Security Basics List <security-basics () securityfocus com>
> Subject: Re: Blocking WMF Files via Squid
> Date: Tue, 3 Jan 2006 13:18:19 -0500
>
>
>
>
>
> I think this is a good idea, but  it is not only *.wmf extensions that have
> this vulnerability, it is all files that have windows metafile headers that
> will open with the Windows Picture and Fax Viewer. As long as your AV is
> up-to-date you should be fine, however, it's not as fun, nor educational,
> as what you did. What would be nice is if their was a way to filter these
> type of headers.
>
> Their was an email to bugtraq (Arian Evans) explaining in detail this
> exploit, if anyone wants it I can forward it to the group, I just don't
> want to repeat it if everyone has already read it.
>
>
>
>
> R. James Stull
> Network Administrator
> Email - stullrj () cat com
>
>
>
>              "Gaddis, Jeremy
>              L."
>              <jeremy@linuxwiz.
>              net>                                                       To
>                                                                         To
>              12/29/2005 10:17          Security Basics List
>              PM                        <security-basics () securityfocus com>
>                                                                         cc
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>                                                                    Subject
>                                        Blocking WMF Files via Squid
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> Caterpillar: Confidential Green                 Retain Until: 02/02/2006
>                                                 Retention Category:  G90 -
>                                                 General
>                                                 Matters/Administration
>
>
> In response to the new 0-day WMF exploit, the educational institution
> for which I work recently took two steps to mitigate a possible infection.
>
> The first step was filtering files with the ".wmf" extension at the
> e-mail gateway via McAfee's Groupshield.  The other step was to block
> URLs ending in ".wmf" through Squid, the caching proxy server (through
> which all of our HTTP traffic is transparently proxied).
>
> I have detailed the few steps that were needed to do this at
> http://www.jeremygaddis.com/2005/12/29/blocking-wmf-at-the-perimeter/
> in the event that it might be useful for others looking to do the same.
>
> Please feel free to comment or provide feedback that may be of benefit.
>
> Thanks,
> -j
>
> --
> Jeremy L. Gaddis, GCWN, Linux+, Network+
> http://www.jeremygaddis.com/
>
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EARN A MASTER OF SCIENCE IN INFORMATION ASSURANCE - ONLINE
The Norwich University program offers unparalleled Infosec management 
education and the case study affords you unmatched consulting experience. 
Tailor your education to your own professional goals with degree 
customizations including Emergency Management, Business Continuity Planning, 
Computer Emergency Response Teams, and Digital Investigations. 

http://www.msia.norwich.edu/secfocus
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