Vulnerabilities in Microsoft Office Excel Could Cause Remote Code Execution

Microsoft Security Bulletin MS09-009 – Critical

Version: 1.0

General Information

Executive Summary

This security update resolves a privately reported and a publicly disclosed vulnerability. The vulnerabilities could allow remote code execution if the user opens a specially crafted Excel file. An attacker who successfully exploited these vulnerabilities could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

This security update is rated Critical for all supported editions of Microsoft Office Excel 2000. For all supported editions of Microsoft Office Excel 2002, Microsoft Office Excel 2003, Microsoft Office Excel 2007, Microsoft Office 2004 for Mac, and Microsoft Office 2008 for Mac; all supported versions of Microsoft Office Excel Viewer; and Microsoft Office Compatibility Pack Service Pack 1, this security update is rated Important. For more information, see the subsection, Affected and Non-Affected Software, in this section.

This security update addresses these vulnerabilities by modifying the way that Microsoft Office Excel opens Excel files. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

This security update also addresses the vulnerability first described in Microsoft Security Advisory 968272.

Recommendation. Microsoft recommends that customers apply the update immediately.