Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to execute code on the targeted system.
The vulnerability is due to the improper validation of files that are used by the Windows Authenticode Signature Verification function. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to run a crafted file or application that is designed to execute arbitrary code on the system.
Microsoft has confirmed this vulnerability in a security bulletin and has released updated software.
Indicators of Compromise
The following Microsoft products are affected:
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 Server 2003 for Itanium-based Systems 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
Windows Server 2008 for Itanium based Systems SP2 and prior
Windows 7 for 32-bit Systems SP1 and prior
Windows 7 for x64-based Systems SP1 and prior
Windows Server 2008 R2 for x64-based Systems SP1 and prior
Windows Server 2008 R2 for Itanium-based Systems SP1 and prior
The vulnerability is triggered when a user or application runs a specially crafted, signed portable executable (PE) file on an affected system that is not verified correctly by the WinVerifyTrust function.
An unauthenticated, remote attacker could exploit this vulnerability by modifying an existing signed executable file. The attacker could modify an existing signed executable file by leveraging an unverified portion of the file in such a way as to add malicious code without invalidating the existing signature of the file. The attacker would then need to have a user or application run the file on the affected system. If successful, the attacker could execute arbitrary code in the context of the user or application.
To exploit the vulnerability, the attacker may provide the user with the crafted PE file or convince the user to visit a malicious website that is hosting the crafted PE file. The attacker is likely to use misleading language or instructions to convince the user to open the crafted file or visit the malicious website.
The update Microsoft has provided addresses this vulnerably by performing strict Windows Authenticode signature verification when verifying portable executable files.
Administrators are advised to apply the appropriate updates.
Users are advised not to open unsolicited e-mail attachments. Users should verify that attachments are safe before opening them.
Administrators are advised to monitor affected systems.
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: MS12-024
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.