Secunia

Description
Tavis Ormandy has discovered a vulnerability in Microsoft Windows, which can be exploited by malicious people to compromise a user's system.

The vulnerability is caused due to an error when processing escaped URLs through Microsoft Windows Help and Support Center (helpctr.exe). This can be exploited to bypass restrictions normally imposed by the "-FromHCP" command-line argument and pass arbitrary parameters to local help documents.

Successful exploitation allows execution of arbitrary commands through the use of an additional input sanitation error in the sysinfomain.htm help document when opening a specially crafted "hcp://" URL.

The vulnerability is confirmed in Windows XP SP3 with Windows Media Player 9 and Internet Explorer 8. Windows Server 2003 is also reportedly affected.

Solution
Apply patches.
Further details available in Customer Area

Provided and/or discovered by
Tavis Ormandy

Changelog
Further details available in Customer Area

Original Advisory
MS10-042 (KB2229593):
http://www.microsoft.com/technet/security/bulletin/ms10-042.mspx

Tavis Ormandy:
http://archives.neohapsis.com/archives/fulldisclosure/2010-06/0197.html

Other references
Further details available in Customer Area

Alternate/detailed remediation
Further details available in Customer Area

Deep Links
Links available in Customer Area