Digital Armaments Security Advisory 12.20.2005: WEBsweeper/MIMEsweeper Executable File Content Check bypass Vulnerability
WEBsweeper/MIMEsweeper Executable File Content Check bypass Vulnerability
Digital Armaments advisory is 12.15.2005
http://www.digitalarmaments.com/2005161283546323.html
I. Background
WEBsweeeper/MIMEsweeper is a commercial software that brings policy-based
content security to the HTTP gateway. For many information or detail about the
software you can refer to the vendor's homepage:
http://www.mailsweeper.com/
II. Problem Description
An attacker could trick a user to click on a mail link/attachment to download
and run a malicious code (any malicious application in a .exe file). The ".exe"
files should be filtered according to the security policies, but an attacker
can trick to fail this test if the data sent to the webserver does not include
the ".exe" extension. This problem persist on all platform where the data sent
to a webserver (GET or POST) is fetched via a server side language (asp, php,
etc..) that doesn't explicitly contain those regular expression. An example is:
http://yourattack.server/asp?cmd=data&maliciouscodewithnumber&number=123
III. Detection
This problem has been detected on latest version of WEBsweeper and MIMEsweeper
actually avaiable and on prior version. It persist on all platforms.
IV. Impact analisys
Successful exploitation allow an attacker to easily trick a user to execute
malicious code on his system. This attack bypass the protection offered by
those content filter application. No exploit code is required. This attack can
also be use in a massive way versus clients systems.
V. Solution
The vendor has given no response.
First notification 12.15.2005.
Second notification 12.19.2005.
VI. Credit
Oliver Muenchow - o.muenchow@xxxxxxxxxxxxx is credited with this discovery.
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time of publishing based on currently available
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