This security update is being released out of band in conjunction with Microsoft Security Bulletin MS09-035, which describes vulnerabilities in those components and controls that have been developed using vulnerable versions of the Microsoft Active Template Library (ATL). As a defense-in-depth measure, this Internet Explorer security update helps mitigate known attack vectors within Internet Explorer for those components and controls that have been developed with vulnerable versions of ATL as described in Microsoft Security Advisory (973882) and Microsoft Security Bulletin MS09-035.
This security update also resolves three privately reported vulnerabilities in Internet Explorer. These vulnerabilities could allow remote code execution if a user views a specially crafted Web page using Internet Explorer. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
This security update is rated Critical for Internet Explorer 5.01 and Internet Explorer 6 Service Pack 1, running on supported editions of Microsoft Windows 2000; Critical for Internet Explorer 6, Internet Explorer 7, and Internet Explorer 8 running on supported editions of Windows XP; Critical for Internet Explorer 7 and Internet Explorer 8 running on supported editions of Windows Vista; Moderate for Internet Explorer 6, Internet Explorer 7, and Internet Explorer 8 running on supported editions of Windows Server 2003; and Moderate for Internet Explorer 7 and Internet Explorer 8 running on supported editions of Windows Server 2008. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses these vulnerabilities by modifying the way that Internet Explorer handles objects in memory and table operations. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection under the next section, Vulnerability Information.
Recommendation. The majority of customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.
For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service.
See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.
Known Issues. Microsoft Knowledge Base Article 972260 documents the currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues.
Microsoft Security Response Center
Microsoft Security Bulletin Summary for July 2009