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. http://telussecuritylabs.com/vulnerabilities