Microsoft Internet Explorer contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on the targeted system.
The vulnerability is due to improper memory operations performed by Internet Explorer. An unauthenticated, remote attacker could exploit this vulnerability by convincing a targeted user to view a malicious website. If successful, the attacker could execute arbitrary code on the targeted system with the privileges of the targeted user.
Microsoft has confirmed the vulnerability in a security bulletin and released software updates.
Indicators of Compromise
Microsoft Internet Explorer 6, 7, 8, 9, and 10 are vulnerable when running on the following systems:
Windows XP SP3 and Professional x64 Edition SP2
Windows Server 2003, x64 Edition and Itanium-based Systems SP2
Windows Vista and x64 Edition SP2
Windows Server 2008 for 32-bit, x64-based Systems and Itanium-based Systems SP2
Windows 7 for 32-bit and x64-based Systems SP1 and prior
Windows Server 2008 R2 for x64-based and Itanium-based Systems SP1 and prior
Windows 8 for 32-bit and 64-bit Systems
Windows Server 2012
The specific flaw exists within the handling of CMarkupBehaviorContext objects by Internet Explorer. Processing a document element by the object could force the browser to reuse a dangling pointer that has been freed.
An unauthenticated, remote attacker could exploit this vulnerability by convincing a targeted user to view a malicious website. When processed, malicious content within the website could cause Internet Explorer to free previously removed or uninitialized memory areas, resulting in a use-after-free error that could corrupt memory. The attacker could leverage the memory corruption to execute arbitrary code on the targeted system with the privileges of the targeted 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.
Administrators are advised to apply the appropriate updates.
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.
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 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 affected systems.
Microsoft has released a security bulletin at the following link: MS13-021
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.