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Credit:
The information has been provided by iDefense Labs Security Advisories.
The original article can be found at: http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=632
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Vulnerable Systems:
* Microsoft DirectX version 7.x
* Microsoft DirectX version 8.x
Immune Systems:
* Microsoft DirectX version 9.0c
This vulnerability exists in the DirextShow SAMI parser, which is implemented in quartz.dll. When the SAMI parser copies parameters into a stack buffer, it does not properly check the length of the parameter. As such, parsing a specially crafted SAMI file can cause a stack-based buffer overflow. This allows an attacker to execute arbitrary code.
Analysis:
Exploitation allows an attacker to execute arbitrary code in the context of the current user.
In order to exploit this vulnerability, an attacker must persuade a user to open a malicious SAMI file. This can be accomplished by hosting a malicious SAMI file on a web site or by sending the malicious file to a user via e-mail or instant message.
It is important to note that a SAMI file does not necessarily have to end with a .smi or .sami extension. DirectShow will identify the file based on the file contents.
If "Web View Content" is enabled in Windows Explorer, which is the default setting, a single click will open the malicious file in the preview pane and trigger the vulnerability.
DirectX 9.0c is listed as an optional update for Windows 2000 operating system in Windows Update site. It is not listed as a critical update. However, installing this update will remove this vulnerability.
Workaround:
To prevent exploitation of this vulnerability, upgrade to DirectX 9.0c or newer.
If upgrading is not possible, you can prevent access to the vulnerable code by un-registering quartz.dll as shown below. However, this workaround will disable image, audio, and video rendering in DirectX-enabled applications.
C:\> regsvr32 -u %windir%\system32\quartz.dll
Vendor response:
Microsoft has addressed this vulnerability within Microsoft Security Bulletin MS07-064. For more information, consult their bulletin at the following URL. http://www.microsoft.com/technet/security/Bulletin/MS07-064.mspx
CVE Information:
CVE-2007-3901
Disclosure timeline:
09/28/2007 - Initial vendor notification
10/09/2007 - Initial vendor response
12/11/2007 - Coordinated public disclosure
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