Public Vulnerability Reports

Microsoft Excel 2003 Malformed Formula Memory Corruption Vulnerability

11.03.08

BACKGROUND

Microsoft Excel is the spreadsheet application that is 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 2003 could allow attackers to execute arbitrary code in the context of the currently logged on user.

This vulnerability specifically exists due to the improper handling of malformed formulas. By creating a document containing a specially crafted formula, an attacker is able to cause memory corruption that leads to arbitrary code execution.

ANALYSIS

Exploitation allows an attacker to execute arbitrary code in the context of the currently logged on user. In order to exploit this vulnerability, the attacker must persuade a user to open a specially crafted Excel (XLS) document. Likely attack vectors include sending the file as an e-mail attachment or linking to the file on a website.

DETECTION

iDefense has confirmed the existence of this vulnerability in Excel 2003 SP2. Other versions may also be affected.

WORKAROUND

Disabling support for legacy binary file formats in the registry will prevent exploitation of this issue. However, this workaround is not available for all versions of Microsoft Excel.

VENDOR RESPONSE

Microsoft has officially addressed this vulnerability with Security Bulletin MS08-014. A fix for this issue was originally included as part of Office 2003 SP3. For more information, consult their bulletin at the following URL.

http://www.microsoft.com/technet/security/Bulletin/ms08-014.mspx

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2008-0115 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

07/27/2007 Initial vendor notification
07/27/2007 Initial vendor response
03/11/2008 Coordinated public disclosure

CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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LEGAL NOTICES

Copyright © 2008 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.