iDefense Security Advisory 02.12.08: Microsoft Office Works Converter Heap Overflow Vulnerability
iDefense Security Advisory 02.12.08
http://labs.idefense.com/intelligence/vulnerabilities/
Feb 12, 2008
I. BACKGROUND
Microsoft Works is a word processor created by Microsoft in the 1980s.
Microsoft Office, a widely use productivity suite, is distributed with
converters for various versions of the Works file format.
II. DESCRIPTION
Remote exploitation of a heap corruption vulnerability in Microsoft
Corp.'s Works Converter, as included with Microsoft Office, could
potentially allow an attacker to execute arbitrary code as the current
user.
This vulnerability stems from improper input validation of OLE
structures within wkcvqd01.dll when converting a Microsoft Works
document (WPS extension) to Rich Text Format (RTF). When certain fields
are modified, such as the length or count values, heap corruption can
occur. This leads to a potentially exploitable condition.
III. ANALYSIS
Exploitation allows attackers to execute arbitrary code as the user that
converts a specially crafted Works document.
Exploitation might require the installation of additional Microsoft
Office components. When installing Microsoft Office, there are several
installation options for converters. In corporate environments, the
required components are usually set to be installed from the hard drive
on first use. However, one of the installation options causes a request
for the installation media. If this option is used, the media prompt
may help mitigate exploitation.
Microsoft first released a fix for this vulnerability as part of Office
2003 SP3. No specific mention was made about this vulnerability at that
time.
IV. DETECTION
iDefense has confirmed that wkcvqd01.dll version 7.03.0616.0, as
included with Microsoft Office 2003, is vulnerable to this issue. Older
versions are assumed to be vulnerable as well. Additionally, Microsoft
Works itself is suspected to be vulnerable.
V. WORKAROUND
User awareness is the best defense against this type of attack. Users
should be reminded not to open attachments or click URLs from untrusted
sources.
VI. VENDOR RESPONSE
Microsoft has officially addressed this vulnerability with Security
Bulletin MS08-011. For more information, consult their bulletin at the
following URL.
http://www.microsoft.com/technet/security/Bulletin/ms08-011.mspx
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-0216 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
11/13/2006 Initial vendor notification
11/14/2006 Initial vendor response
09/17/2007 Office 2003 SP3 released (fix included)
02/12/2008 Coordinated public disclosure
IX. CREDIT
This vulnerability was reported to VeriSign iDefense by Damian Put
(pucik@xxxxxxxxxxx).
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X. LEGAL NOTICES
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at the time of publishing based on currently available information. Use
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