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iDefense Security Advisory 12.09.08
Dec 09, 2008
Microsoft Windows graphics device interface (GDI) enables applications
to use graphics and formatted text on both the video display and the
printer. For more information about GDI, please visit the following Web
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
This vulnerability exists in the way GDI handles integer math. An
integer overflow could occur while calculating the a buffer length,
which results in an undersized heap buffer being allocated. This buffer
is then overflowed with data from the input image file.
Exploitation allows an attacker to execute arbitrary code with the
privileges of the current user. Exploitation would require convincing a
targeted user to view a specially crafted image file. An attacker could
host this file on a Web server, attach the file to an e-mail or
embedded the file in an Office document.
This vulnerability also can be triggered through e-mail. If the e-mail
client can automatically display images embedded in the e-mail, the
user only needs to open the e-mail to trigger the vulnerability.
Currently an EMF file is used as a test attack vector. Outlook and
Outlook Express will automatically display EMF images and trigger the
vulnerability. Lotus Notes and Thunderbird do not display EMF images in
e-mail directly, but the vulnerability still can be triggered when
opening or viewing the EMF attachment.
iDefense has confirmed that gdi32.dll file version 5.1.2600.3316, as
included in fully patched Windows XP Service Pack 2 as of May 2008, is
vulnerable. Other versions of Windows are suspected to be vulnerable.
Turning off metafile processing by modifying the registry mitigates this
threat. 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 does not affect processes that are already running, so you
might need to log off and log on again or restart the computer after
making the change. Note 2: It only blocks one attack vector through
Windows metafile. It is possibly to exploit this vulnerability through
other attack vectors.
Impact of Workaround: components relying on metafile processing might
not work properly, such as printing.
Viewing e-mail in plain text format mitigates e-mail-based attack.
VI. VENDOR RESPONSE
"The vulnerability could allow remote code execution if a user opens a
specially crafted WMF image file. An attacker who successfully
exploited this vulnerability could take complete control of an affected
system. An attacker could then install programs; view, change, or delete
data; or create new accounts."
Microsoft Corp. has released a patch which addresses this issue. For
more information, consult their advisory at the following URL.
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-2249 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
VIII. DISCLOSURE TIMELINE
05/21/2008 Initial Vendor Notification
05/21/2008 Initial Vendor Reply
09/05/2008 Additional Information Provided to Vendor
10/14/2008 Additional Vendor Feedback
12/09/2008 Coordinated Public Disclosure
This vulnerability was discovered by Jun Mao of iDefense based on a
submission from an anonymous contributor.
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X. LEGAL NOTICES
Copyright =A9 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.
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