Microsoft Windows Metafile Handling Buffer Overflow
- Systems running Microsoft Windows
Microsoft Windows is vulnerable to remote code execution via an error in handling files using the Windows Metafile image format. Exploit code has been publicly posted and used to successfully attack fully-patched Windows XP SP2 systems. However, other versions of the the Windows operating system may be at risk as well.
Microsoft Windows Metafiles are image files that can contain both vector and bitmap-based picture information. Microsoft Windows contains routines for displaying various Windows Metafile formats. However, a lack of input validation in one of these routines may allow a buffer overflow to occur, and in turn may allow remote arbitrary code execution.
This new vulnerability may be similar to one Microsoft released patches for in Microsoft Security Bulletin MS05-053. However, publicly available exploit code is known to affect systems updated with the MS05-053 patches.
Not all anti-virus software products are currently able to detect all known variants of exploits for this vulnerability. However, US-CERT recommends updating anti-virus signatures as frequently as practical to provide maximum protection as new variants appear.
A remote, unauthenticated attacker may be able to execute arbitrary code if the user is persuaded to view a specially crafted Windows Metafile.
Since there is no known patch for this issue at this time, US-CERT is recommending sites follow several potential workarounds.
WorkaroundsPlease refer to the Solution section of US-CERT Vulnerability Note for the latest workarounds we are aware of: Microsoft has suggested a procedure for disabling SHIMGVW.DLL in the Suggested Actions+Workarounds+ section of Microsoft Security Advisory (912840):
Feedback can be directed to US-CERT.