Additional technical information is available to address the Microsoft Office Excel stack-based buffer overflow arbitrary code execution vulnerability.
Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system.
The vulnerability is due to a memory corruption error when the affected software parses a crafted Excel file with a modified data structure. An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious document to a user and convincing the user to open the document. When processed in Excel, the document may trigger memory corruption that the attacker could use to execute arbitrary code on the system with the privileges of the user.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
The following Microsoft products are affected:
Microsoft Excel 2007 SP3 and prior
Microsoft Excel 2010 (32-bit editions) SP1 and prior
Microsoft Excel 2010 (64-bit editions) SP1 and prior
Microsoft Office for Mac 2011
Microsoft Excel Viewer
Microsoft Office Compatibility Pack SP3 and prior
To exploit the vulnerability, the attacker may provide a file to the user and persuade the user to open or execute the file by using misleading language or instructions.
Microsoft addresses the vulnerability by modifying the way Microsoft Excel validates the FEAT data structure.
Microsoft has released a security bulletin at the following link: MS12-076
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code on the system with the privileges of the user. If the user holds elevated privileges, the attacker could execute code that results in a complete system compromise.
The vulnerability is due to a memory corruption error when the affected software parses a crafted Excel file with a modified data structure. The insufficient validation of the supplied counter value size, used by the affected software while parsing Feature11 and Feature12 records, could result in a stack overflow condition in memory.
An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious document to a user and convincing the user to open the document. When processed in Excel, the document may trigger memory corruption that the attacker could use to execute arbitrary code on the system with the privileges of the user.
Administrators are advised to apply the appropriate updates.
Users are advised not to open e-mail messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in e-mail messages are safe, they are advised not to open them.
Administrators may consider applying the Microsoft Office Isolated Conversion Environment (MOICE) to safely open Word, Excel, and PowerPoint 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.
Administrators are advised to monitor affected systems.
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 Microsoft Update service. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
Version 1, November 13, 2012, 9:23 AM: Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system. Updates are available.
Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats
Original Release SP2, SP3
Microsoft Office Excel Viewer
Office for Mac
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