TELUS Security Labs VR - Microsoft Office Excel Malformed Records Stack Buffer Overflow

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Microsoft Office Excel Malformed Records Stack Buffer Overflow

 TSL ID   : FSC20090609-01
 Reference: http://telussecuritylabs.com/threats/show/FSC20090609-01

1. Affected Software

  Microsoft Office Excel 2000
  Microsoft Office Excel 2002

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

2. Vulnerability Summary

A remotely exploitable vulnerability has been discovered in Microsoft Office Excel products. Specifically, the 
vulnerability is due to a design error encountered when parsing Excel files which contain malformed records. Remote 
attackers can exploit this vulnerability by enticing target users to open a malicious Excel file.

3. Vulnerability Analysis

A remote attacker can exploit the vulnerability by sending a malicious Excel file to the target system and enticing the 
target user to open it. A successful code execution attempt will result in the execution of arbitrary code within the 
security privileges of the currently logged in user. An unsuccessful attack attempt will result in abnormal termination 
of the Microsoft Office Excel application.

4. Vulnerability Detection

TELUS Security Labs has confirmed the vulnerability in:

  Microsoft Office Excel 2000

5. Workaround

Apply the vendor's patch, remove file associations to affected files, or block Excel resources originating from 
untrusted networks.

6. Vendor Response

Microsoft has released a bulletin addressing this vulnerability. 

Reference: http://www.microsoft.com/technet/security/bulletin/MS09-021.mspx

7. Disclosure Timeline

  2008-12-23 Reported to vendor
  2008-12-23 Initial vendor response
  2009-06-09 Vendor disclosure

8. Credits

Vulnerability Research Team, TELUS Security Labs

9. References

  CVE: FSC20090609-01
  Vendor: MS09-021

10. About TELUS Security Labs Vulnerability Research Service

The Vulnerability Research Service (VRS) gives an in-depth understanding of the mechanisms and properties of software 
vulnerabilities. This service provides lab-based analysis of vulnerabilities based on disassembly, protocol analysis, 
and source-code analysis.

Our vulnerability data enables security product vendors to deliver product updates without the need for additional 
research. This data also gives MSPs and enterprise security teams the tools and knowledge to more effectively protect 
their environments without time-consuming research.

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