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iDefense Security Advisory 11.10.09
http://labs.idefense.com/intelligence/vulnerabilities/
Nov 10, 2009

I. BACKGROUND

Microsoft Word is a word processing application that is part of the
Microsoft Office suite of products. For more information about
Microsoft Word, see following web site.

http://office.microsoft.com/en-us/word/default.aspx

II. DESCRIPTION

Remote exploitation of a stack buffer overflow vulnerability in
Microsoft Corp.'s Word could allow attackers to execute arbitrary code
with the privileges of the targeted user.

This vulnerability occurs when Word parses the File Information Block
(FIB) structure inside a Word document. When a malformed FIB structure
is processed, a stack buffer overflow will occur which can lead to an
exploitable condition.

III. ANALYSIS

Exploitation allows remote attackers to execute arbitrary code on the
affected host under the context of the user opening the file.

Exploitation might require that the user open a specially crafted word
document with a vulnerable application. The most likely exploitation
vector involves convincing a user to open a word document sent to them
via e-mail or linked on a website.

IV. DETECTION

iDefense has confirmed fully patched Microsoft Word 2003 SP3, Microsoft
Word XP SP3, Microsoft Word 2000 SP3 are vulnerable.

Microsoft Word 2007 SP1 is not affected.

V. WORKAROUND

iDefense is currently unaware of any effective workaround for this
issue. Since the vulnerability occurs in the core parsing code, it is
not possible to disable the affected module.

User awareness is the best defense against this type of attack. Users
should not follow links or open attachments from untrusted sources or
that are received unexpectedly from trusted sources.

VI. VENDOR RESPONSE

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

http://www.microsoft.com/technet/security/bulletin/MS09-068.mspx

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2009-3135 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

03/06/2009  - Initial Contact
03/07/2009  - Initial Response
05/21/2009  - Tentative disclosure set for September
06/25/2009  - Requested CVE from Vendor
11/10/2009  - Coordinated Public Disclosure

IX. CREDIT

This vulnerability was discovered by Jun Mao, iDefense Labs.

Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php

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http://labs.idefense.com/

X. LEGAL NOTICES

Copyright © 2009 iDefense, Inc.

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 customerservice@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.
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