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Microsoft Excel Memory Corruption Vulnerability

12.04.11

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/

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 specially crafted Excel file. Specific values within this file can trigger a memory corruption vulnerability and may allow arbitrary code execution.

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.

DETECTION

The following Microsoft products are vulnerable:

  • Excel 2002 SP3
  • Excel 2002 SP3
  • Excel 2003 SP3
  • Office 2004 for Mac
  • Office 2008 for Mac
  • Open XML File Format Converter for Mac

WORKAROUND

The vulnerability occurs in the core parsing code of Excel, and this code can not be disabled; however, it is possible to disable the opening of the older binary format files and use MOICE to convert the file to the newer XML-based format.

VENDOR RESPONSE

Microsoft Corp. has released patches which address this issue. Information about downloadable vendor updates can be found by clicking on the URLs shown.

http://www.microsoft.com/technet/security/bulletin/ms11-021.mspx

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-0103 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

09/09/2010 Initial Vendor Notification
09/09/2010 Initial Vendor Reply
04/12/2011 Coordinated Public Disclosure

CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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LEGAL NOTICES

Copyright © 2011 Verisign, Inc.

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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.