Microsoft Office Excel ExternName Buffer Overflow Vulnerability (CVE-2010-1249)

                                                "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
affecting Microsoft Office Excel.

The vulnerability is caused by a buffer overflow error when processing
malformed ExternName (recType 0x23) records, which could be exploited by
attackers to execute arbitrary code by tricking a user into opening
a specially crafted Excel document.


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

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


IV. Binary Analysis & Proof-of-concept
---------------------------------------

In-depth binary analysis of the vulnerability and a proof-of-concept
have been published by VUPEN through the VUPEN Binary Analysis & Exploits
portal :

http://www.vupen.com/exploits/


V. SOLUTION
----------------

Apply MS10-038 security update:
http://www.microsoft.com/technet/security/bulletin/ms10-038.mspx


VI. CREDIT
--------------

The vulnerability was discovered by Nicolas Joly of VUPEN Security