iDefense Security Advisory 09.13.11 http://labs.idefense.com/intelligence/vulnerabilities/ Sep 13, 2011
I. BACKGROUND Excel is the spreadsheet application included with Microsoft Corp.'s Office productivity software suite. More information is available at the following website: http://office.microsoft.com/excel/ II. DESCRIPTION Remote exploitation of a memory corruption vulnerability in Microsoft Corp.'s Excel could allow an attacker to execute arbitrary code with the privileges of the current user. The vulnerability occurs when Excel parses a certain specially crafted record in an Excel file. An invalid value of the length field in the record header can trigger an error condition and result in using memory content which has already been freed and may allow arbitrary code execution. III. ANALYSIS Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the user opening the file. To exploit this vulnerability, an attacker needs to convince a user to open a malicious file. Attackers typically accomplish this by e-mailing a targeted user the file or hosting the file on a Web page. IV. DETECTION Microsoft has reported the following products vulnerable: * Microsoft Excel 2003 SP 3 * Microsoft Excel 2007 SP 2 * Microsoft Office 2007 SP 2 * Microsoft Excel 2010 (32-bit editions) * Microsoft Excel 2010 SP 1 (32-bit editions) * Microsoft Office 2010 and Microsoft Office 2010 SP 1 (32-bit editions) * Microsoft Excel 2010 (64-bit editions) * Microsoft Excel 2010 SP 1 (64-bit editions) * Microsoft Office 2010 and Microsoft Office 2010 SP 1 (64-bit editions) * Microsoft Office 2004 for Mac * Microsoft Office 2008 for Mac * Microsoft Office for Mac 2011 * Open XML File Format Converter for Mac * Microsoft Excel Viewer SP 2 * Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP 2 * Excel Services * Microsoft Excel Web App 2010 and Microsoft Excel Web App 2010 SP 1 V. WORKAROUND Microsoft suggested workarounds can be found under the Workaround section within Microsoft Security Bulletin MS11-072. http://technet.microsoft.com/en-us/security/bulletin/ms11-072 VI. VENDOR RESPONSE Microsoft has released fixes which addresses this issue. Information about downloadable vendor updates can be found by clicking on the URLs shown. http://technet.microsoft.com/en-us/security/bulletin/ms11-072 VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-1986 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 02/16/2011 Initial Vendor Notification 02/16/2011 Vendor Reply 09/13/2011 Coordinated Public Disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2011 Verisign Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please e-mail customerserv...@idefense.com for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.
