Microsoft has re-released a security advisory and issued a knowledge base article that addresses software compatibility issues in the fix for the Microsoft Internet Explorer uninitialized object memory access vulnerability.
Description
Microsoft Internet Explorer 6 SP2 and prior, Internet Explorer 7, and Internet Explorer 8 contain a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the user.
The vulnerability is due to unsafe memory operations by Internet Explorer. An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to view a malicious website. If the user views the site, the attacker could execute arbitrary code on the affected system.
Microsoft has confirmed this vulnerability in a security bulletin and released software updates.
Warning Indicators
Microsoft Internet Explorer 6 SP2 and prior, Internet Explorer 7, and Internet Explorer 8 are vulnerable when running on the following affected Windows products:
Windows 2000 SP4 and prior
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
IntelliShield Analysis
To exploit this vulnerability, the attacker must convince the user to view a malicious website. An attacker may provide links to malicious sites via e-mail messages. The attacker may also embed malicious content into public websites, triggering exploits against any users who visit that site.
Systems that restrict user privileges are at less risk because any code execution would run with limited privileges. An exploit on a system on which the user holds elevated privileges could allow the attacker to gain complete control over the affected system.
The Cisco Applied Intelligence team has created an Applied Mitigation Bulletin to address vulnerabilities that Microsoft disclosed in the October 2009 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 October 2009
Microsoft has released a knowledge base article to address software compatibility issues in the fix for this vulnerability. The knowledge base article can be found at the following link: 976749
Vendor Announcements
Microsoft has re-released a security bulletin at the following link: MS09-054
Impact
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code with the privileges of the user. If that user holds privileges equal to those of the Administrator account, the attacker could execute code that could result in a complete system compromise.
Technical Information
This vulnerability is due to an implementation error in the copy constructor of a specific Document Object Module (DOM) object in Microsoft Internet Explorer. Copies of objects may maintain references to single properties. The deletion of an object and the deallocation of its properties could trigger a double-free error, corrupting memory areas.
An unauthenticated, remote attacker could exploit the vulnerability by convincing a user to view a website containing malicious DOM objects. The creation and removal of a malicious object could cause the application to operate on uninitialized memory areas, causing memory corruption that the attacker could make use of to execute arbitrary code with the privileges of the user.
Safeguards
Administrators are advised to apply the available software updates.
Users are advised to read e-mail messages in plain text.
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 are advised to use an unprivileged account when browsing the Internet.
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.
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 2, October 14, 2009, 10:32 AM: Additional technical information is available to describe the Microsoft Internet Explorer uninitialized object memory access vulnerability.
Version 1, October 13, 2009, 2:21 PM: Microsoft Internet Explorer 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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