Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code.
The vulnerability is due to improper processing of malformed Advanced Systems Format (ASF) file headers. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious media file. If the user views the file, the attacker could execute arbitrary code with the privileges of the user.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates that correct it.
Indicators of Compromise
The following Microsoft systems are vulnerable:
Windows 2000 SP4 and prior
Windows XP SP3 and prior
Windows XP Professional x64 Edition SP2 and prior
Windows Server 2003 SP2 and prior
Windows Server 2003 x64 Edition SP2 and prior
Windows Vista SP2 and prior
Windows Vista x64 Edition SP2 and prior
Windows Server 2008 for 32-bit Systems SP2 and prior
Windows Server 2008 for x64-based Systems SP2 and prior
The following Microsoft applications are affected:
Windows Media Format SDK version 9.0
Windows Media Format SDK version 9.5
Windows Media Format SDK x64 Edition version 9.5
Windows Media Format SDK version 11
Windows Media Services 9.1
Windows Media Services 2008
The vulnerability is due to improper processing of malformed ASF file headers. The Windows Media Format Runtime wmvcore.dll component fails to properly handle malicious ASF media files. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious media file. The processing of the file could trigger the execution of arbitrary code with the privileges of the user.
Attackers have no way to directly exploit this vulnerability and instead rely on user interaction to accomplish an exploit. An attacker may attempt to convince the user to view a malicious media file by providing links to users in e-mail messages. Attackers may also attempt to embed malicious content on public or compromised websites in the hopes that users will access those sites on their own.
If an exploit is successful, the attacker could execute arbitrary code with the privileges of the user. Windows XP systems that grant users Administrator privileges may be at greatest risk because an attacker could execute code resulting in a complete system compromise. Other systems may be at a reduced risk because users may run applications with reduced privileges.
The update available from Microsoft corrects this vulnerability by improving the parsing of ASF files.
Administrators are advised to apply the available software updates.
Administrators may consider restricting access to the wmvcore.dll component.
Users are advised not to visit websites or follow links that have suspicious characteristics or cannot be verified as safe.
Users are advised not to open media files from suspicious or unrecognized sources. If users cannot verify that media files are safe, they are advised not to open them.
Users are advised to run applications with the least necessary privileges.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Microsoft has released a security bulletin at the following link: MS09-047
Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Windows Update website. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.