Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code. Updates are available.
Description
Microsoft Office Excel versions 2002 SP3 and prior, 2003 SP3 and prior, and 2003 SP3 and prior contain a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
This vulnerability is due to errors when the vulnerable application processes malformed SxView records within 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 Viewer 2003 SP3 and prior
IntelliShield Analysis
An attacker must rely on user participation to accomplish an exploit by convincing a user to view a malicious document. The attacker send the document as an e-mail attachment to the user. The attacker may use social engineering techniques to try and convince users to open the attachment.
If an exploit is successful, the attacker could execute arbitrary code with the privileges of the user. A system that grants the user elevated privileges could be completely compromised in the event of an exploit, because any executed code may run with Administrator privileges.
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 that user holds Administrator privileges, the attacker could completely compromise the system.
Technical Information
This vulnerability is due to errors when the vulnerable application processes malformed SxView records within Excel documents. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious Excel file. If a user opens the Excel document, the document could trigger memory corruption to enable the attacker 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.
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