VUPEN Security Research - Microsoft Office Excel Formula Record Heap 
Corruption Vulnerability

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

Twitter : http://twitter.com/vupen


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

"Microsoft Office Excel is a powerful tool you can use to create and format
spreadsheets, and analyze and share information to make more informed
decisions. With the Microsoft Office Fluent user interface, rich data
visualization, and PivotTable views, professional-looking charts are easier
to create and use." (microsoft.com)


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

VUPEN Vulnerability Research Team discovered a critical vulnerability
in Microsoft Office Excel.

The vulnerability is caused by a heap corruption error when processing
malformed Formula records within an Excel document, which could be exploited
by attackers to compromise a vulnerable system by tricking a user into
opening a specially crafted XLS document.


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

Microsoft Office 2010
Microsoft Office 2007 Service Pack 2
Microsoft Office 2003 Service Pack 3
Microsoft Office 2002 Service Pack 3


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

In-depth binary analysis of the vulnerability and a code execution exploit
are available through the VUPEN Binary Analysis & Exploits Service :

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 MS11-072 security updates.


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/ms11-072
http://www.vupen.com/english/research.php


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

2010-06-25 - Vulnerability Discovered by VUPEN and shared with TPP customers
2011-09-14 - Public disclosure