A vulnerability has been reported in Internet Explorer, which can be exploited by malicious people to compromise a user's system.

The vulnerability is caused due to a boundary error in the "CMimeFt::Start()" function within urlmon.dll when processing URLs on a website using HTTP 1.1 and compression. This can be exploited to cause a heap-based buffer overflow via an overly long URL (more than 260 bytes).

Successful exploitation allows execution of arbitrary code when a user is e.g. tricked into visiting a malicious website.

The vulnerability affects Internet Explorer 6 SP1 on Windows 2000 and Windows XP SP1 and was introduced by the MS06-042 patches.

Solution
Apply patch.
Further details available to Secunia VIM customers

Provided and/or discovered by
Independently discovered by:
* Dejan Kovacevic, Bold Internet Solutions.
* Derek Soeder, eEye Digital Security.
* Hu Qianwei, NSFocus Security Team.

Changelog
Further details available to Secunia VIM customers

Original Advisory
MS06-042 (KB918899):
http://www.microsoft.com/technet/security/bulletin/MS06-042.mspx

Microsoft:
http://www.microsoft.com/technet/security/advisory/923762.mspx
http://support.microsoft.com/kb/923762/
http://blogs.technet.com/msrc/archive/2006/08/24/449860.aspx

eEye Digital Security:
http://research.eeye.com/html/advisories/published/AD20060824.html

NSFocus Security Team:
http://www.nsfocus.com/english/homepage/research/0608.htm

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers