iDefense Security Advisory 04.08.08: Microsoft Windows Graphics Rendering Engine Integer Overflow Vulnerability
iDefense Security Advisory 04.08.08
http://labs.idefense.com/intelligence/vulnerabilities/
Apr 08, 2008
I. BACKGROUND
Microsoft Windows graphics device interface (GDI) is the core library
used to display graphics and text on the Windows operating system. It
is the standard interface through which applications access the
graphics rendering engine. For more information, see the vendor's site
found at the following link.
http://msdn2.microsoft.com/en-us/library/ms536795(VS.85).aspx
II. DESCRIPTION
Remote exploitation of an integer overflow vulnerability in multiple
versions of Microsoft Corp.'s Windows operating system could allow an
attacker to execute arbitrary code with the privileges of the current
user.
The vulnerability occurs when parsing a header structure that describes
a bitmap contained in the file. Several values from this header are
used in an arithmetic operation that calculates the number of bytes to
allocate for a heap buffer. This calculation can overflow, which
results in an undersized heap buffer being allocated. This buffer is
then overflowed with data from the file.
III. ANALYSIS
Exploitation allows an attacker to execute arbitrary code with the
privileges of the current user. Exploitation would require convincing a
targeted user to visit a malicious URL through some form of social
engineering.
This vulnerability can also be triggered through e-mail. If the e-mail
client automatically displays images embedded in the e-mail, the user
only needs to open the e-mail to trigger the vulnerability.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in the
following Microsoft products:
Windows 2000 SP4
Windows XP SP2
Windows Server 2003 SP1, SP2, Vista, and Vista SP1 are not affected.
V. WORKAROUND
Turn off metafile processing by modifying the registry.
Under registry key
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\GRE_Initialize
create a DWORD entry "DisableMetaFiles" and set it to 1.
Note 1: This doesn't affect processes that are already running, so you
might need to log off and log in again or restart the computer after
making the change.
Note 2: This workaround only blocks the metafile attack vector. Since
the vulnerable code is in gdi32.dll, it can possibly be reached through
other attack vectors.
Impact of Workaround: components relying on metafile processing might
not work properly, such as printing.
Viewing email in plain text format will mitigate email based attacks.
VI. VENDOR RESPONSE
Microsoft has officially addressed this vulnerability with Security
Bulletin MS08-021. For more information, consult their bulletin at the
following URL.
http://www.microsoft.com/technet/security/bulletin/ms08-021.mspx
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-1083 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
12/17/2007 Initial vendor notification
12/17/2007 Initial vendor response
04/08/2008 Coordinated public disclosure
IX. CREDIT
This vulnerability was discovered by Jun Mao, iDefense Labs.
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http://labs.idefense.com/methodology/vulnerability/vcp.php
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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.