VUPEN Security Research - Microsoft Office Excel Real Time Data Stack 
Overwrite Vulnerability (CVE-2011-0105)

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


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 stack overwrite error when parsing the RTD
RealTimeData record (0813h), which could be exploited by attackers to
compromise a vulnerable system by tricking a user into opening a specially
crafted Excel document.

CVSS Score: 10 (AV:N/AC:L/Au:N/C:C/I:C/A:C)


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

Microsoft Office 2008 for Mac
Microsoft Office 2004 for Mac
Microsoft Excel 2002 Service Pack 3
Open XML File Format Converter for Mac


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


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

To proactively protect critical networks and infrastructures against 
unpatched
vulnerabilities and reduce risks related to zero-day attacks, VUPEN shares 
its
vulnerability research with governments and organizations members of the 
VUPEN
Threat Protection Program (TPP).

VUPEN TPP customers receive fully detailed and technical reports about 
security
vulnerabilities discovered by VUPEN and in advance of their public 
disclosure.

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


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

Apply the MS11-021 security update.


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

This vulnerability was discovered by Nicolas Joly of VUPEN Security


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

VUPEN is a leading IT security research company providing vulnerability
management and security intelligence solutions which enable enterprises
and institutions to eliminate vulnerabilities before they can be exploited,
ensure security policy compliance and meaningfully measure and manage risks.

Governmental and federal agencies, and global enterprises in the financial
services, insurance, manufacturing and technology industries rely on VUPEN
to improve their security, prioritize resources, cut time and costs, and
stay ahead of the latest threats.

* VUPEN Vulnerability Notification Service (VNS) :
http://www.vupen.com/english/services/vns-index.php

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

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

* VUPEN Web Application Security Scanner (WASS) :
http://www.vupen.com/english/services/wass-index.php


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

http://www.vupen.com/english/research-vuln.php
http://www.vupen.com/english/advisories/2011/0940
http://www.microsoft.com/technet/security/Bulletin/MS11-021.mspx


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

2010-10-10 - Vulnerability Discovered by VUPEN
2011-04-12 - MS11-021 security update available