This security update resolves several privately reported vulnerabilities in Microsoft Active Template Library (ATL). The vulnerabilities could allow remote code execution if a user loaded a specially crafted component or control hosted on a malicious website. 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 all supported editions of Microsoft Windows 2000 Service Pack 4, Windows XP, Windows Server 2003, Windows Vista, and Windows Server 2008. For more information on the software affected by this update, see the subsection, Affected and Non-Affected Software, in this section. For more information on the impact of, and workarounds and mitigations for controls and components that may be vulnerable to these issues, please see Microsoft Security Advisory (973882).
The security update addresses the vulnerabilities by modifying the ATL headers so that components and controls built using the headers can safely initialize from a data stream, and by providing updated versions of Windows components and controls built using corrected ATL headers. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.
How does this bulletin relate to the vulnerabilities described in Microsoft Security Advisory (973882)?This bulletin addresses Windows components that are affected by the Active Template Library (ATL) vulnerabilities described in Microsoft Security Advisory (973882).
Is this security update related to MS09-034, released as an out-of-band update on July 28, 2009?
Yes. Microsoft Security Bulletin MS09-034, "Cumulative Security Update for Internet Explorer," includes a mitigation that helps prevent components and controls built using the vulnerable ATL from being exploited in Internet Explorer, as well as addressing multiple unrelated vulnerabilities. The new defense in depth protections offered in MS09-034 include updates to Internet Explorer 5.01, Internet Explorer 6 and Internet Explorer 6 Service Pack 1, Internet Explorer 7, and Internet Explorer 8, that monitor and help prevent the successful exploitation of all known public and private ATL vulnerabilities, including the vulnerabilities that could lead to bypassing ActiveX's Kill Bit Security Feature. These protections are designed to help protect customers from Web-based attacks.
If I have installed the MS09-034 update, do I still need to install this update?
Yes. This security bulletin update addresses vulnerabilities in Windows components. By installing this update, users ensure that all known issues caused by vulnerable ATL headers and libraries are corrected for core Windows components.
If I have installed the MS09-034 update, do I still need to install additional components and controls issued by third-parties that address the vulnerabilities described in Microsoft Security Advisory 973882 and Microsoft Security Bulletin MS09-035?Yes, you need to install updated controls from third parties when released. The MS09-034 Internet Explorer mitigation does not address the underlying vulnerabilities within certain components and controls developed with the Active Template Library. Microsoft recommends that developers follow the guidance provided in this bulletin to modify and rebuild all components and controls affected by vulnerabilities described in this bulletin.
Are third-party components and controls affected by this issue?Some third-party components and controls may be affected by this issue if certain conditions were met during the building of the components and controls. Microsoft recommends that developers follow the guidance provided in this bulletin to modify and rebuild all components and controls affected by vulnerabilities described in this bulletin.
What is the scope of the vulnerability?
This is a remote code execution vulnerability. The vulnerability could allow remote code execution if the user visits a specially crafted Web page with Internet Explorer, instantiating a vulnerable component or control. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user.
Is this security update related to MS09-032?
Yes. Microsoft Security Bulletin MS09-032, "Cumulative Security Update of ActiveX Kill Bits," includes ActiveX kill bits for msvidctl.dll as a part of CVE-2008-0015. This bulletin, MS09-037, also addresses components affected by CVE-2008-0015. In MS09-032, kill bits were provided for msvidctl.dll, since that component was never intended to be instantiated within Internet Explorer. The components addressed in this bulletin may be instantiated, and have been updated to address the core issue covered by CVE-2008-0015.
If I have installed the MS09-032 update, do I still need to install this update?
Yes. This security update addresses vulnerabilities in Windows components. By installing this update, users ensure that all known issues caused by vulnerable ATL headers and libraries are corrected for core Windows components.
What does the update do?
The update addresses the vulnerability by correcting the affecting Window components and controls to restrict data read from untrusted streams to ensure it is not copied directly to the memory stack.
What does the update do?
The update addresses the issue by correcting Windows components and control to restrict the Load method of the IPersistStreamInit interface to only allow calls to memcopy with trusted data.
A remote code execution vulnerability exists in the Microsoft Active Template Library (ATL) due to a bug in the ATL headers that could allow an attacker to force VariantClear to be called on a VARIANT that has not been correctly initialized. Because of this bug, the attacker can control what happens when VariantClear is called during handling of an error by supplying a corrupt stream. This vulnerability only directly affects systems with components and controls installed that were built using Visual Studio ATL. This vulnerability could allow a remote, unauthenticated user to perform remote code execution on an affected system. An attacker could exploit the vulnerability by constructing a specially crafted Web page. When a user views the Web page, the vulnerability could allow remote code execution.
What is the scope of the vulnerability?
This is a remote code execution vulnerability. The vulnerability could allow remote code execution if the user visits a specially crafted Web page with Internet Explorer that instantiates a vulnerable component or control. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user.
What causes the vulnerability?
The vulnerability results from an issue in the ATL headers that could allow an attacker to call VariantClear() on a variant that has not been correctly initialized. For developers who created a component or control using ATL in this manner, the resulting component or control could allow remote code execution in the context of the logged on user.
Are third-party ActiveX controls affected by this issue?
Some third-party components and controls may be affected by this issue if certain conditions were met during the building of the components and controls. Microsoft recommends that developers follow the guidance provided in theMS09-035 Visual Studio bulletin to modify and rebuild all components and controls affected by vulnerabilities described in this bulletin.
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