Additional technical information that describes the Microsoft Internet Explorer select tag processing arbitrary code execution vulnerability is available.
Description
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 a memory corruption error in the affected software when processing certain malformed HTML elements that are embedded in a web page. An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to view a malicious web page. If successful, the attacker could execute arbitrary code on the system with the privileges of the user.
Microsoft confirmed this vulnerability in a security bulletin and released software updates.
Warning Indicators
Internet Explorer version 8 is vulnerable when running on the following Microsoft 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 Itanium-based 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
Windows Server 2008 Itanium-based Edition SP2 and prior
Windows 7 for 32-bit Systems
Windows 7 for x64-based Systems
Windows Server 2008 R2 for x64-based Systems
Windows Server 2008 R2 for Itanium-based Systems
IntelliShield Analysis
An attacker cannot directly exploit this vulnerability and instead relies on user interaction to accomplish an exploit. The attacker must convince the user to visit a malicious web page. The attacker may use social engineering techniques, such as links delivered in e-mail or instant messages combined with instructions to perform the necessary actions. However, because of the number of steps required, an exploit may be difficult to achieve.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the December 2010 security bulletin release. This Cisco bulletin, which assists administrators in identifying or mitigating these vulnerabilities using Cisco devices, is available at the following link: Cisco Applied Mitigation Bulletin: Microsoft Security Bulletin Release for December 2010
Vendor Announcements
Microsoft has released a security bulletin at the following link: MS10-090
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If the user holds elevated privileges, the attacker could execute code that results in a complete system compromise.
Technical Information
The vulnerability is due to improper memory operations performed by the affected software while handling the select tag.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a targeted user to open a crafted web page that has a particular element in the select tag. The processing of the web page could cause the vulnerable application to unexpectedly free the contents of the select tag. Later, accessing of the memory object could trigger a memory corruption. The attacker could exploit the memory corruption to execute arbitrary code with the privileges of the user.
Safeguards
Administrators are advised to apply the appropriate software updates.
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 unsolicited e-mail attachments. Users should verify that attachments are safe before opening them.
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.
Patches/Software
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.
Signatures
Cisco Systems Cisco Intrusion Prevention System (IPS) 6.0
Version 1, December 14, 2010, 1:35 PM: Microsoft Windows contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the user. Updates are available.
Home Edition Base, SP1, SP2, SP3 | Professional Edition Base, SP1, SP2, SP3 | Professional x64 (AMD/EM64T) Base, SP2
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