Secunia Research: Microsoft Excel Substream Parsing Integer Underflow Vulnerability

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                     Secunia Research 12/04/2011

- Microsoft Excel Substream Parsing Integer Underflow Vulnerability -

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Table of Contents

Affected Software....................................................1
Severity.............................................................2
Vendor's Description of Software.....................................3
Description of Vulnerability.........................................4
Solution.............................................................5
Time Table...........................................................6
Credits..............................................................7
References...........................................................8
About Secunia........................................................9
Verification........................................................10

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1) Affected Software 

* Microsoft Excel 2002 SP3
* Microsoft Excel 2003 SP3
* Microsoft Excel 2007 SP2
* Microsoft Excel 2010

NOTE: Other versions may also be affected.

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2) Severity 

Rating: Highly critical
Impact: System compromise
Where:  Remote

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3) Vendor's Description of Software 

"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."

Product Link:
http://office.microsoft.com/en-us/excel/default.aspx

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4) Description of Vulnerability

Secunia Research has discovered a vulnerability in Microsoft Excel, 
which can be exploited by malicious people to compromise a user's 
system.

The vulnerability is caused by an integer underflow error when parsing
data included in a 400h substream. This can be exploited to cause a 
stack-based buffer overflow via a specially crafted Excel file.

Successful exploitation allows execution of arbitrary code.

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5) Solution 

Apply patches provided by MS11-021.

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6) Time Table 

29/03/2010 - Vendor notified.
30/03/2010 - Vendor response.
27/04/2010 - Vendor provides status update.
25/05/2010 - Vendor provides status update.
30/09/2010 - Vendor provides status update (scheduled for bulletin
             release in February 2011).
10/02/2011 - Vendor provides status update (scheduled for bulletin
             release in March 2011).
02/03/2011 - Vendor provides status update (scheduled for bulletin
             release in April 2011).
06/04/2011 - Vendor provides status update.
12/04/2011 - Public disclosure.

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7) Credits 

Discovered by Alin Rad Pop, Secunia Research.

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8) References

The Common Vulnerabilities and Exposures (CVE) project has assigned
CVE-2011-0097 for the vulnerability.

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9) About Secunia

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10) Verification 

Please verify this advisory by visiting the Secunia website:
http://secunia.com/secunia_research/2011-31/

Complete list of vulnerability reports published by Secunia Research:
http://secunia.com/secunia_research/

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