iDefense Security Advisory 11.09.10: Microsoft Word RTF File Parsing Stack Buffer Overflow Vulnerability

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iDefense Security Advisory 11.09.10
http://labs.idefense.com/intelligence/vulnerabilities/
Nov 09, 2010

I. BACKGROUND

Microsoft Word is a word processing application from Microsoft Office.
For more information about Microsoft Word, see the following website:
http://office.microsoft.com/en-us/word/default.aspx

Rich-Text Format (RTF) is a document file format developed by Microsoft
for cross-platform document interchange.

II. DESCRIPTION

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

This vulnerability specifically exists in the handling of a specific
control word in an RTF document. Under certain circumstances, Word will
copy its property strings into a stack buffer without checking the
length, which causes a stack buffer overflow.

III. ANALYSIS

Exploitation allows remote attackers to execute arbitrary code on the
affected host under the context of the user who opened the malicious
RTF document with Microsoft Word.

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

Since Outlook 2007 uses the Word engine to process e-mails, it is also
affected by this vulnerability. The attacker can send the user a
specially crafted RTF e-mail. When this e-mail is opened or displayed
in the preview pane using Outlook 2007, the vulnerability will be
triggered.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in Microsoft
Word 2003, Microsoft Word 2007, and Microsoft Outlook 2007. The
following Microsoft products are vulnerable:

    * Microsoft Office XP SP 3
    * Microsoft Office 2003 SP 3
    * Microsoft Office 2007 SP 2
    * Microsoft Office 2010 (32-bit editions)
    * Microsoft Office 2010 (64-bit editions)
    * Microsoft Office for Mac 2011

V. WORKAROUND

Microsoft recommends reading e-mail in plain-text format as a
workaround.

VI. 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/MS10-087.mspx

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2010-3333 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

08/12/2009  Initial Vendor Notification
08/12/2009  Initial Vendor Reply
11/09/2010  Coordinated Public Disclosure

IX. CREDIT

This vulnerability was reported to iDefense by wushi of team509.

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X. LEGAL NOTICES

Copyright © 2010 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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