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                     Secunia Research 09/06/2009

        - Microsoft Excel String Parsing Integer Overflow  -

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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 Office Excel 2003

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/excel 

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4) Description of Vulnerability

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

The vulnerability is caused due to an integer overflow error when 
processing the number of strings in a file and can be exploited to 
cause a heap-based buffer overflow via a specially crafted Excel 
file.

Successful exploitation allows execution of arbitrary code.

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5) Solution 

Apply patches from MS09-021.

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6) Time Table 

10/03/2009 - Vendor notified.
10/03/2009 - Vendor response.
19/05/2009 - Status update requested.
22/05/2009 - Vendor provides status update.
09/06/2009 - Public disclosure.

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7) Credits 

Discovered by Carsten Eiram, Secunia Research.

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8) References

The Common Vulnerabilities and Exposures (CVE) project has assigned 
CVE-2009-0561 for the vulnerability.

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9) About Secunia

Secunia offers vulnerability management solutions to corporate
customers with verified and reliable vulnerability intelligence
relevant to their specific system configuration:

http://secunia.com/advisories/business_solutions/ 

Secunia also provides a publicly accessible and comprehensive advisory
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http://secunia.com/advisories/mailing_lists/ 

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10) Verification 

Please verify this advisory by visiting the Secunia website:
http://secunia.com/secunia_research/2009-12/ 

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

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