Microsoft Security Bulletin MS09-037 - Critical

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

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.

If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

What causes the vulnerability? 
The function CComVariant::ReadFromStream used in the ATL header does not properly restrict untrusted data read from a stream. This issue could lead to reading data directly onto the stack instead of reading it into the area of memory allocated for an array.

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.

Are third-party ActiveX controls affected by this issue?
Although this vulnerability is in Microsoft ATL, it is not in the ATL version shipped with Visual Studio. The affected ATL headers reside in a private header file that shipped in Windows XP and Windows Server 2003. Most third-party developers use the header file that came with Visual Studio. These applications are not exposed to this vulnerability.

What might an attacker use the vulnerability to do? 
If a user has a vulnerable control on their system and an attacker bypasses the mitigations described in Microsoft Security Advisory (973882), then an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

How could an attacker exploit the vulnerability? 
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer by attempting to exploit a vulnerable control, and then convince a user to view the Web site. This can also include compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have to discover a vulnerable control, and force users to visit these Web sites. To do this, an attacker would have to convince users to visit the Web site, typically by getting them to click a link in an e-mail message or in an Instant Messenger request that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability? 
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who should not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.

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.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? 
Yes. When the security bulletin was released, Microsoft had received information that this vulnerability was being exploited.

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

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.

If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

What causes the vulnerability? 
The vulnerability is caused by an error in the Load method of the IPersistStreamInit interface. The Load method could allow calls to memcopy with untrusted data.

Are third-party ActiveX controls affected by this issue?
Although this vulnerability is in Microsoft ATL, it is not in the ATL version shipped with Visual Studio. The affected ATL headers reside in a private header file that shipped in Windows XP and Windows Server 2003. Most third-party developers use the header file that came with Visual Studio. These applications are not exposed to this bug.

What might an attacker use the vulnerability to do? 
If a user has a vulnerable control on their system and an attacker bypasses the mitigations described in Microsoft Security Advisory (973882), then an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

How could an attacker exploit the vulnerability? 
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer by attempting to exploit a vulnerable control, and then convince a user to view the Web site. This can also include compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have to discover a vulnerable control, and force users to visit these Web sites. To do this, an attacker would have to convince users to visit the Web site, typically by getting them to click a link in an e-mail message or in an Instant Messenger request that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability? 
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who should not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.

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.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? 
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

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.

If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

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.

What might an attacker use the vulnerability to do? 
If a user has a vulnerable control on their system and an attacker bypasses the mitigations described in Microsoft Security Advisory (973882), then an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

How could an attacker exploit the vulnerability? 
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer by attempting to exploit a vulnerable control, and then convince a user to view the Web site. This can also include compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have to discover a vulnerable control, and force users to visit these Web sites. To do this, an attacker would have to convince users to visit the Web site, typically by getting them to click a link in an e-mail message or in an Instant Messenger request that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

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.

I am a third-party application developer and I use ATL in my components and controls. Are my components and controls vulnerable, and if so, how do I update them? 
For instructions on determining whether your components and controls are vulnerable and how to update them, see the following MSDN Article.

What systems are primarily at risk from the vulnerability? 
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who should not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do? 
The update addresses the issue by updating Windows components and controls to ensure VariantClear() can only be called on initialized variants.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? 
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

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.

If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

What causes the vulnerability? 
The vulnerability results from errors in the ATL headers that handle instantiation of an object from data streams. For components and controls built using ATL, unsafe usage of OleLoadFromStream could allow the instantiation of arbitrary objects which can bypass certain related security policies.

What might an attacker use the vulnerability to do? 
If a user has a vulnerable control on their system, and an attacker bypasses the mitigations described in Microsoft Security Advisory (973882), then if the user is logged on with administrative user rights an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

How could an attacker exploit the vulnerability? 
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer by attempting to exploit a vulnerable control, and then convince a user to view the Web site. This can also include compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have to discover a vulnerable control, and force users to visit these Web sites. To do this, an attacker would have to convince users to visit the Web site, typically by getting them to click a link in an e-mail message or in an Instant Messenger request that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

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.

I am a third-party application developer and I use ATL in my components and controls. Are my components and controls vulnerable, and if so, how do I update them? 
For instructions on determining whether your components and controls are vulnerable and how to update them, see the following MSDN Article.

What systems are primarily at risk from the vulnerability? 
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who should not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do? 
The update addresses the vulnerability by correcting the manner in which ATL handles the instantiation of objects from data stream and providing updated versions of Windows components and controls built using corrected ATL headers.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? 
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Mitigating factors and Workarounds for potentially vulnerable components and controls are located in Microsoft Security Advisory (973882).

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.

If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

What causes the vulnerability? 
The vulnerability is caused by a bug in the ATL header that could allow reading a variant from a stream and leaving the variant type read with an invalid variant. When deleting the variant, it would be possible to free unintended areas in memory that could be controlled by an attacker, resulting in inconsistent memory contents and execution of malicious code.

Are third-party ActiveX controls affected by this issue?
Although this vulnerability is in Microsoft ATL, it is not in the ATL version shipped with Visual Studio. The affected ATL headers reside in a private header file that shipped in Windows XP and Windows Server 2003. Most third-party developers use the header file that came with Visual Studio. These applications are not exposed to this issue.

What might an attacker use the vulnerability to do? 
If a user has a vulnerable control on their system, and an attacker bypasses the mitigations described in Microsoft Security Advisory (973882), then if the user is logged on with administrative user rights an attacker could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 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.

How could an attacker exploit the vulnerability? 
An attacker could host a specially crafted Web site that is designed to exploit this vulnerability through Internet Explorer by attempting to exploit a vulnerable control, and then convince a user to view the Web site. This can also include compromised Web sites and Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have to discover a vulnerable control, and force users to visit these Web sites. To do this, an attacker would have to convince users to visit the Web site, typically by getting them to click a link in an e-mail message or in an Instant Messenger request that takes users to the attacker's Web site. It could also be possible to display specially crafted Web content by using banner advertisements or by using other methods to deliver Web content to affected systems.

What systems are primarily at risk from the vulnerability? 
Workstations and terminal servers are primarily at risk. Servers could be at more risk if users who should not have sufficient administrative permissions are given the ability to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do? 
The update addresses the issue by properly validating variants read from a stream and providing updated versions of Windows components and controls built using corrected ATL headers.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited? 
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

Note For supported versions of Windows XP Professional x64 Edition, this security update is the same as supported versions of the Windows Server 2003 x64 Edition security update.

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.

Reference Table

The following table contains the security update information for this software. You can find additional information in the subsection, Deployment Information, in this section.