Vulnerability Note VU#134756

Microsoft Windows buffer overflow in Enhanced Metafile rendering API

An EMF image is a 32-bit format that can contain both vector information and bitmap information. This format is an improvement over the Windows Metafile Format and contains extended features. For more information about image types and formats, see Microsoft Knowledge Base Article 320314. Additional information about these file formats is also available at the MSDN Library Web Site.

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

Do not access EMF files from untrusted sources

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

Attackers may host malicious EMF 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

http://secunia.com/advisories/14631/
http://www.securityfocus.com/bid/12834/info/
http://www.securityfocus.com/archive/1/393571
http://www.microsoft.com/technet/security/Bulletin/MS05-053.mspx

Credit

Thanks to Microsoft and Hongzen Zhou for reporting this vulnerability.

This document was written by Ken MacInnis.

Other Information

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