iDefense Security Advisory 08.12.08: Microsoft Office WPG Image File Heap Buffer Overflow Vulnerability

iDefense Security Advisory 08.12.08
http://labs.idefense.com/intelligence/vulnerabilities/
Aug 12, 2008

I. BACKGROUND

Microsoft Office contains a number of input filters. These input filters
allow transparent conversion from external types into a form that the
Office applications can use. More information on import filters in
Microsoft Office 2002 is available at the following URL.

http://support.microsoft.com/?scid=kb;en-us;290362

II. DESCRIPTION

Remote exploitation of a buffer overflow vulnerability in Microsoft
Corp.'s Office filter for WordPerfect Graphics Files, could allow an
attacker to execute arbitrary code with the privileges of the victim.

This vulnerability specifically lies within the "WPGIMP32.FLT" module. A
heap overflow can occur when processing a malformed Wordperfect Graphics
(WPG) file. By corrupting heap memory, it is possible to execute
arbitrary code.

III. ANALYSIS

Exploitation allows an attacker to execute arbitrary code in the context
of the targeted user. In order to exploit this issue, a targeted user
must process an attacker supplied WPG file with Microsoft Office. This
issue could be exploited by using a malformed WPG file, or by using a
Wordperfect document containing such a file.

By default, Microsoft Office Products do not register the WPG or WP file
types and the system will prompt the user for the application to open
the files with. Additionally the Microsoft Web Service does not offer
suggestions as to which application to use to open these extensions.

The Word Perfect Importer is not installed by default and may require an
installation CD in order to install this feature. Users will likely be
shown a dialog asking if they wish to install this Importer upon
opening a Word Perfect document file type.

IV. DETECTION

iDefense has confirmed this vulnerability in the following versions of
Microsoft Office; Office XP SP3, Office 2003 SP2, Office 97. Other
versions may also be affected.

V. WORKAROUND

iDefense is currently unaware of any effective workaround for this
issue.

VI. VENDOR RESPONSE

Microsoft has officially addressed this vulnerability with Security
Bulletin MS08-044. For more information, consult their bulletin at the
following URL.

http://www.microsoft.com/technet/security/bulletin/ms08-044.mspx

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-3460 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

11/07/2006 Initial vendor notification
11/07/2006 Initial vendor response
08/12/2008 Coordinated public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Damian Put.

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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
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.