Vulnerability Note VU#134756

Microsoft Windows buffer overflow in Enhanced Metafile rendering API

Original Release date: 08 Nov 2005 | Last revised: 09 Nov 2005

Overview

Microsoft Windows Enhanced Metafile Format image rendering routines contain a buffer overflow flaw that may allow an attacker to cause a denial-of-service condition.

Description

Microsoft describes the Enhanced Metafile Format (EMF) as the following:

    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.


The Microsoft Windows EMF rendering routines may fail to properly check a buffer length, possibly resulting in a crash of the affected application or in the application failing to respond. Any program that uses these routines to render a specially-crafted image file is vulnerable to the issue.

Proof of concept code related to this issue is known to be available at this time.

Impact

A remote, unauthenticated attacker may cause an affected application to stop responding or crash.

Solution

Apply an update
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 (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected-08 Nov 2005
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

Thanks to Microsoft and Hongzen Zhou for reporting this vulnerability.

This document was written by Ken MacInnis.

Other Information

  • CVE IDs: CVE-2005-0803
  • Date Public: 18 Mar 2005
  • Date First Published: 08 Nov 2005
  • Date Last Updated: 09 Nov 2005
  • Severity Metric: 7.56
  • Document Revision: 16

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