Additional technical information that describes the Microsoft Office Excel MDXTUPLE record processing heap overflow vulnerability is available.
Microsoft Office Excel contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to errors in processing malformed Excel documents.† An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to view a malicious document.† If the user views the document, the attacker could execute arbitrary code with the privileges of the user.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates.
The following Microsoft products are affected:
Office Excel 2007 SP2 and prior
Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2 and prior
An attacker cannot directly exploit this vulnerability and instead must rely on user interaction to accomplish an exploit.† The attacker must convince a user to view a malicious document, likely provided as an attachment to an e-mail message delivered to the user.† The attacker may use social engineering techniques to make the user more likely to open a provided document.
If the exploit is successful, the attacker could trigger the execution of arbitrary code with the privileges of the user.† If that user holds elevated privileges, the attacker could gain complete control over the system.† An exploit involving a user with restricted privileges is likely to result in a limited system compromise because any code executed would run in a limited security context.
Microsoft has released a security bulletin at the following link: MS10-017
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the targeted user.† If that user holds elevated privileges, the attacker could execute code resulting in a complete system compromise.
This vulnerability is due to insufficient boundary checks on MDXTUPLE records in Microsoft Excel Workbook global streams. The MDXTUPLE records maintain the metadata required for external data connections.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a targeted user to view a malicious Microsoft Excel document that contains a crafted MDXTUPLE record broken into several overly large records. Processing the malicious document could cause a heap-based buffer overflow, corrupting memory. An attacker could take advantage of the memory corruption to execute arbitrary code on the targeted system with the privileges of the user.
Administrators are advised to apply the available software 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 possible.
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.
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.
Version 1, March 9, 2010, 1:40 PM: 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.
The security vulnerability applies to the following combinations of products.
2007 Base, SP1, SP2
Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats
Original Release Base, SP1, SP2
2007 Base, SP1, SP2
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.