Secunia

Rubén Santamarta has discovered a vulnerability in Microsoft Windows, which potentially can be exploited by malicious people to compromise a user's system.

The vulnerability is caused due to a boundary error in the Infotech Storage System Library (itss.dll) when reading a ".CHM" file. This can be exploited to cause heap corruption and may allow arbitrary code execution via a specially crafted ".CHM" file.

Successful exploitation requires that the user is e.g. tricked in opening or decompiling a malicious ".CHM" file using "hh.exe".

The vulnerability has been confirmed in Windows XP SP2 (fully patched) and also reported in Windows 2000 SP4. Other versions may also be affected.

NOTE: The CHM file format should be considered insecure and treated similar to an executable file. However, this vulnerability is triggered even when the user decompiles the file without opening it.

Solution
The vulnerability will reportedly be fixed in the next Service Pack.
Further details available in Customer Area

Provided and/or discovered by
Rubén Santamarta

Changelog
Further details available in Customer Area

Original Advisory
http://reversemode.com/index.php?option=com_content&task=view&id=11&Itemid=1

Deep Links
Links available in Customer Area