Microsoft Internet Explorer contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system.
The vulnerability is due to errors in processing input to the execCommand() method in Internet Explorer. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious website. If successful, the attacker could exploit this vulnerability to execute arbitrary code on the system with the privileges of the user.
Functional code that demonstrates an exploit of this vulnerability is publicly available.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
Indicators of Compromise
Microsoft Internet Explorer versions 6, 7, 8, and 9 are vulnerable when running on the following systems:
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 with SP2 for Itanium-based Systems 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 due to errors in processing input to the execCommand() method in Internet Explorer. Improper handling of input to the vulnerable function could cause Internet Explorer to access previously removed or uninitialized memory areas, corrupting memory.
An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious web page. Processing the web page could trigger memory corruption, which the attacker could use to execute arbitrary code on the system with the privileges of the user.
To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.
Reports have indicated that this vulnerability is being actively exploited in the wild.
Administrators are advised to apply the appropriate updates.
Users are advised not to open e-mail messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in e-mail messages are safe, they are advised not to open them.
Administrators running Internet Explorer on Windows Server 2003, Windows Server 2008, or Windows Server 2008 R2 are advised to ensure Enhanced Security Configuration is enabled. This mode is enabled by default and mitigates this vulnerability.
Administrators may consider installing the Enhanced Mitigation Experience Toolkit v3.0 (EMET) which helps prevent software vulnerabilities from being successfully exploited for code execution. Additional information, including a link to download EMET v3.0, is available at the following link: Knowledgebase Article 2458544
Administrators are advised to apply the Microsoft-Fix-It solution that prevents exploitation of this vulnerability for some scenarios. Additional information, including a link to apply the solution, is available at the following link: Microsoft Fix it 50939
Administrators are advised to monitor affected systems.
Microsoft has released a security bulletin at the following link: MS12-063
Microsoft has released a security advisory at the following link: 2757760
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 Microsoft Update service. 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.