Vulnerability Note VU#433341

Microsoft Windows vulnerable to buffer overflow via specially crafted WMF file

Overview

Microsoft Windows may be vulnerable to remote code execution via a buffer overflow in the Windows Metafile image format handling.

I. Description

Windows Metafile (WMF) format images are metafiles that can contain both vector and bitmap-based information. Microsoft Windows contains routines for displaying WMF files. However, a lack of input validation in on of these routines may allow a buffer overflow to occur, and in turn may allow remote arbitrary code execution.

II. Impact

A remote, unauthenticated attacker may be able to execute arbitrary code if the user is persuaded to view a specially-crafted WMF file.

III. Solution

Apply an update

Please see Microsoft Security Bulletin MS05-053 for details on updates, workarounds, and solutions.

Do not access WMF files from untrusted sources

Exploitation occurs by accessing a specially crafted WMF file (typically .wmf). By only accessing WMF files from trusted or known sources, the chances of exploitation are reduced.

Attackers may host malicious WMF files on a website. In order to convince users to visit their sites, those attackers often use URL encoding, IP address variations, long URLs, intentional misspellings, and other techniques to create misleading links. Do not click on unsolicited links received in email, instant messages, web forums, or internet relay chat (IRC) channels. Type URLs directly into the browser to avoid these misleading links. While these are generally good security practices, following these behaviors will not prevent exploitation of this vulnerability in all cases, particularly if a trusted site has been compromised or allows cross-site scripting.

Systems Affected

Vendor	Status	Date Updated
Microsoft Corporation	Vulnerable	8-Nov-2005

References

http://www.microsoft.com/technet/security/Bulletin/MS05-053.mspx
http://www.eeye.com/html/research/advisories/AD20051108b.html

Credit

Thanks to Microsoft for reporting this vulnerability, who in turn thank Venustech AdDLab, eEye Digital Security and Peter Ferrie of Symantec Security Response for information on the issue.

This document was written by Ken MacInnis.

Other Information

Date Public	11/08/2005
Date First Published	11/08/2005 03:30:59 PM
Date Last Updated	11/09/2005
CERT Advisory
CVE-ID(s)	CVE-2005-2124
NVD-ID(s)	CVE-2005-2124
US-CERT Technical Alerts
Metric	10.94
Document Revision	8

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Produced 2005 by US-CERT, a government organization
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