iDefense Security Advisory 03.11.08
http://labs.idefense.com/intelligence/vulnerabilities/
Mar 11, 2008

I. 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/

II. DESCRIPTION

Remote exploitation of a heap corruption vulnerability in Microsoft
Corp.'s Excel spreadsheet application allows attackers to execute
arbitrary code in the context of the user who started Excel.

The vulnerability exists in the handling of DVAL records in BIFF8 format
spreadsheet files. When certain fields are set to invalid values, heap
corruption occurs.

III. ANALYSIS

Exploitation allows attackers to execute arbitrary code in the context
of the user who started Excel. Exploitation requires that attackers
persuade users to open a maliciously crafted file in Excel.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in Microsoft
Excel 2003 and Excel 2007. Previous versions may also be affected.

V. 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.

VI. VENDOR RESPONSE

Microsoft has officially addressed this vulnerability with Security
Bulletin MS08-014. Previous releases, specifically Office 2007 SP1 and
Office 2003 SP3, included a fix for this issue. For more information,
consult their bulletin at the following URL.

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

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-0111 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

05/09/2007  Initial vendor notification
05/09/2007  Initial vendor response
03/11/2008  Coordinated public disclosure

IX. CREDIT

This vulnerability was discovered by Greg MacManus, iDefense Labs.

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X. LEGAL NOTICES

Copyright © 2008 iDefense, 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
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