Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the user. Updates are available.
Description
Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
This vulnerability is due to insufficient validation of data within objects that are embedded in Excel documents. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious file. If the user views the file, the attacker could execute arbitrary code on the system with the privileges of the user.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates.
Warning Indicators
The following Microsoft products are vulnerable:
Office Excel 2002 SP3 and prior
Office Excel 2003 SP3 and prior
Office Excel 2007 SP2 and prior
Office Excel Viewer 2003 SP3 and prior
Office Excel Viewer 2007 SP2 and prior
Office 2004 for Mac
Office 2008 for Mac
Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 and prior
IntelliShield Analysis
To exploit this vulnerability, an attacker must rely on user participation. The attacker must deliver a malicious document to the user, likely as an e-mail attachment, and convince the user to open the file. If successful, the attacker could execute arbitrary code on the system with the privileges of the user. If the user holds elevated privileges, the attacker could execute code resulting in a full system compromise.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the November 2009 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin Release for November 2009
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS09-067
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If the user holds elevated privileges equivalent to the Administrator account, the attacker could gain complete control over the system.
Technical Information
This vulnerability exists due to insufficient validation of data within objects that are embedded in Excel documents. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious Excel file. When opened and processed, the document could trigger memory corruption that the attacker could leverage to execute arbitrary code with the privileges of the user.
Safeguards
Administrators are advised to apply the appropriate updates.
Users are advised not to open unsolicited e-mail attachments. Users should verify that attachments are safe before opening them.
Users are advised to run applications with the least privileges necessary.
Users may consider applying the Microsoft Office Isolated Conversion Environment (MOICE) to safely open Excel files from suspicious or unrecognized sources on systems that are running Microsoft Office 2003 or Office 2007.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Patches/Software
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Signatures
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
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