Vulnerability Note VU#427980

Overview

Microsoft Internet Explorer 8 is susceptible to a use-after-free vulnerability in the mshtml.dll library.

Description

The use-after-free vulnerability is triggered when handling circular memory references. Full details of the crash can be found at Michal Zalewski's website. Additional details about the fuzzer used to find this vulnerability can be found at Michal Zalewski's blog.

Impact

An attacker can cause the browser to crash and may be able to execute arbitrary code as the user.

Solution

We are currently unaware of a practical solution to this problem.

Internet Explorer users should take advantage of the mitigations provided in Microsoft's Enhanced Mitigation Experience Toolkit.

Vendor Information (Learn More)

Vendor	Status	Date Notified	Date Updated
Microsoft Corporation	Affected	-	06 Jan 2011

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

• http://lcamtuf.blogspot.com/2011/01/announcing-crossfuzz-potential-0-day-in.html
• http://seclists.org/fulldisclosure/2011/Jan/1
• http://lcamtuf.coredump.cx/cross_fuzz/msie_crash.txt
• http://msdn.microsoft.com/en-us/library/dd361842%28v=vs.85%29.aspx
• http://blogs.technet.com/b/srd/archive/2010/09/02/enhanced-mitigation-experience-toolkit-emet-v2-0-0.aspx

Credit

This vulnerability was reported to the public by Michal Zalewski.

This document was written by Jared Allar.

Other Information

• CVE IDs: CVE-2011-0346
• Date Public: 01 Jan 2011
• Date First Published: 06 Jan 2011
• Date Last Updated: 10 Jan 2011
• Severity Metric: 1.11
• Document Revision: 13