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 improper processing of Vector Markup Language (VML) content in Internet Explorer. An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to visit a malicious site. If successful, the attacker could execute arbitrary code on the system.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
Indicators of Compromise
Microsoft Internet Explorer versions 6, 7, and 8 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 improper handling of VML elements by the affected software. The vulnerability exists when the affected software attempts to access a deleted object. Attempting to access the deleted object could cause a memory corruption error that may allow arbitrary code execution.
An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a website that contains crafted VML content. When processed, the malicious content could cause Internet Explorer to attempt to access a previously deleted object, corrupting memory. Also, the attacker could embed an ActiveX control marked safe for initialization in an application or Office document that uses the Internet Explorer rendering engine. The attacker could take advantage of the memory corruption to execute arbitrary code on the system with the privileges of the user.
To exploit the vulnerability, the attacker may provide a file or a link to a malicious website and use misleading language or instructions to persuade the user to open the file or follow the provided link.
Microsoft has corrected this vulnerability by modifying the way Internet Explorer handles objects in memory.
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.
Users should verify that unsolicited links are safe to follow.
Administrators may consider configuring Internet Explorer to prompt users before running Active Scripting or ActiveX controls by setting the Internet and Local Intranet security zone settings to High. Alternately, administrators could disable Active Scripting and ActiveX controls in these security zones.
Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.
Administrators are advised to monitor critical systems.
Microsoft has released a security bulletin at the following link: MS12-023
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.