VUPEN Security Research - Microsoft Internet Explorer "X-UA-COMPATIBLE" 
Use-after-free Vulnerability

Website : http://www.vupen.com/english/research.php

Twitter : http://twitter.com/vupen


I. BACKGROUND
---------------------

"Microsoft Internet Explorer is a web browser developed by Microsoft and
included as part of the Microsoft Windows line of operating systems with
more than 60% of the worldwide usage share of web browsers." (Wikipedia)


II. DESCRIPTION
---------------------

VUPEN Vulnerability Research Team discovered a vulnerability in Microsoft
Internet Explorer.

The vulnerability is caused by a use-after-free error in the "mshtml.dll"
component when processing the "X-UA-COMPATIBLE" keyword of a "META" tag,
which could be exploited by remote attackers to compromise a vulnerable
system via a specially crafted web page.


III. AFFECTED PRODUCTS
---------------------------

Microsoft Internet Explorer 9
Microsoft Internet Explorer 8
Microsoft Internet Explorer 7
Microsoft Internet Explorer 6

Microsoft Windows 7 for x64-based Systems Service Pack 1
Microsoft Windows 7 for x64-based Systems
Microsoft Windows 7 for 32-bit Systems Service Pack 1
Microsoft Windows 7 for 32-bit Systems
Microsoft Windows Server 2008 R2 for x64-based Systems
Microsoft Windows Server 2008 R2 for x64-based Systems Service Pack 1
Microsoft Windows Server 2008 R2 for Itanium-based Systems
Microsoft Windows Server 2008 R2 for Itanium-based Systems Service Pack 1
Microsoft Windows XP Service Pack 3
Microsoft Windows XP Professional x64 Edition Service Pack 2
Microsoft Windows Server 2003 Service Pack 2
Microsoft Windows Server 2003 x64 Edition Service Pack 2
Microsoft Windows Vista Service Pack 2
Microsoft Windows Vista x64 Edition Service Pack 2
Microsoft Windows Server 2008 for 32-bit Systems Service Pack 2
Microsoft Windows Server 2008 for x64-based Systems Service Pack 2


IV. Binary Analysis & Exploits/PoCs
---------------------------------------

In-depth binary analysis of the vulnerability and a proof-of-concept code
are available through the VUPEN Binary Analysis & Exploits portal :

http://www.vupen.com/english/services/ba-index.php


VUPEN Binary Analysis & Exploits Service provides private exploits and
in-depth technical analysis of the most significant public vulnerabilities
based on disassembly, reverse engineering, protocol analysis, and code 
audit.

The service allows governments and major corporations to evaluate risks, and
protect infrastructures and assets against new threats. The service also
allows security vendors (IPS, IDS, AntiVirus) to supplement their internal
research efforts and quickly develop both vulnerability-based and
exploit-based signatures to proactively protect their customers from attacks
and emerging threats.


V. VUPEN Threat Protection Program
-----------------------------------

Governments and major corporations which are members of the VUPEN Threat
Protection Program (TPP) have been proactively alerted about the 
vulnerability
when it was discovered by VUPEN in advance of its public disclosure, and
have received a detailed attack detection guidance to protect national and
critical infrastructures against potential 0-day attacks exploiting this
vulnerability:

http://www.vupen.com/english/services/tpp-index.php


VI. SOLUTION
----------------

Apply the MS11-081 security update.


VII. CREDIT
--------------

This vulnerability was discovered by Nicolas Joly of VUPEN Security


VIII. ABOUT VUPEN Security
---------------------------

VUPEN is the world leader in vulnerability research for defensive and
offensive cyber security. VUPEN solutions enable corporations and 
governments
to measure and manage risks, eliminate vulnerabilities before they can be
exploited, and protect critical infrastructures and assets against known and
unknown vulnerabilities.

VUPEN has been recently recognized as "Company of the Year in the 
Vulnerability
Research Market (2011)" by Frost & Sullivan.

VUPEN solutions include:

* VUPEN Binary Analysis & Exploits Service (BAE) :
http://www.vupen.com/english/services/ba-index.php

* VUPEN Threat Protection Program (TPP) :
http://www.vupen.com/english/services/tpp-index.php


IX. REFERENCES
----------------------

http://technet.microsoft.com/en-us/security/bulletin/MS11-081
http://www.vupen.com/english/research.php


X. DISCLOSURE TIMELINE
-----------------------------

2011-03-09 - Vulnerability Discovered by VUPEN and shared with TPP customers
2011-10-12 - Public disclosure