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  Microsoft Windows HTML Help ActiveX code execution

From:MICROSOFT <secure_(at)_microsoft.com>
Date:13.02.2007
Subject:Microsoft Security Bulletin MS07-008 Vulnerability in HTML Help ActiveX Control Could Allow Remote Code Execution (928843)

Microsoft Security Bulletin MS07-008
Vulnerability in HTML Help ActiveX Control Could Allow Remote Code Execution (928843)
Published: February 13, 2007

Version: 1.0
Summary

Who Should Read this Document: Customers who use Microsoft Windows

Impact of Vulnerability: Remote Code Execution

Maximum Severity Rating: Critical

Recommendation: Customers should apply the update immediately

Security Update Replacement: This bulletin replaces a prior security update. See the replacement table in the frequently asked questions (FAQ) section for more details.

Caveats: None

Tested Software and Security Update Download Locations:

Affected Software:


Microsoft Windows 2000 Service Pack 4 — Download the update


Microsoft Windows XP Service Pack 2 — Download the update


Microsoft Windows XP Professional x64 Edition — Download the update


Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1 — Download the update


Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based Systems — Download the update


Microsoft Windows Server 2003 x64 Edition — Download the update

Non-Affected Software:


Windows Vista

The software in this list has been tested to determine whether the versions are affected. Other versions either no longer include security update support or may not be affected. To determine the support life cycle for your product and version, visit the Microsoft Support Lifecycle Web site.

Note The security updates for Microsoft Windows Server 2003, Windows Server 2003 Service Pack 1, and Windows Server 2003 x64 Edition also apply to Windows Server 2003 R2.
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General Information

Executive Summary

Executive Summary:

This update resolves a newly discovered, privately reported vulnerability as well as additional issues discovered through internal investigations. The vulnerability is documented in the "Vulnerability Details" section of this bulletin.

On vulnerable versions of Windows, if a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of the client workstation. 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.

We recommend that customers apply the update immediately.

Severity Ratings and Vulnerability Identifiers:
Vulnerability Identifiers Impact of Vulnerability Windows 2000 Service Pack 4 Windows XP Service Pack 2 Windows Server 2003 Windows Server 2003 Service Pack 1

HTML Help ActiveX Control Vulnerability – CVE-2007-0214


Remote Code Execution


Critical


Critical


Moderate


Moderate

This assessment is based on the types of systems that are affected by the vulnerability, their typical deployment patterns, and the effect that exploiting the vulnerability would have on them.

Note By default, Internet Explorer on Windows Server 2003 runs in a restricted mode that is known as Enhanced Security Configuration. This mode mitigates some of the vulnerabilities. See the FAQ section for this security update for more information about Internet Explorer Enhanced Security Configuration.

Note The security updates for Microsoft Windows Server 2003, Windows Server 2003 Service Pack 1, and Windows Server 2003 x64 Edition also apply to Windows Server 2003 R2.

Note The severity ratings for non-x86 operating system versions map to the x86 operating systems versions as follows:


The Microsoft Windows XP Professional x64 Edition severity rating is the same as the Windows XP Service Pack 2 severity rating.


The Microsoft Windows Server 2003 for Itanium-based Systems severity rating is the same as the Windows Server 2003 severity rating.


The Microsoft Windows Server 2003 with SP1 for Itanium-based Systems severity rating is the same as the Windows Server 2003 Service Pack 1 severity rating.


The Microsoft Windows Server 2003 x64 Edition severity rating is the same as the Windows Server 2003 Service Pack 1 severity rating.
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Frequently Asked Questions (FAQ) Related to This Security Update

What updates does this release replace?
This security update replaces a prior security update. The security bulletin ID and affected operating systems are listed in the following table.
Bulletin ID Windows 2000 Service Pack 4 Windows XP Service Pack 2 Windows Server 2003 Windows Server 2003 Service Pack 1

MS06-046


Replaced


Replaced


Replaced


Replaced

What are the known issues that customers may experience when they install this security update?
Microsoft Knowledge Base Article 928843 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues.

Extended security update support for Microsoft Windows XP Home Edition Service Pack 1 or Service Pack 1a, Windows XP Media Center Edition 2002 Service Pack 1, Windows XP Media Center Edition 2004 Service Pack 1, Windows XP Professional Service Pack 1 or Service Pack 1a, and Windows XP Tablet PC Edition Service Pack 1 ended on October 10, 2006. I am still using one of these operating systems; what should I do?
Windows XP (all versions) Service Pack 1 has reached the end of its support life cycle. It should be a priority for customers who have these operating system versions to migrate to supported versions to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit the following Microsoft Support Lifecycle Web site. For more information about the extended security update support period for these operating system versions, visit the Microsoft Product Support Services Web site.

Extended security update support for Microsoft Windows 98, Windows 98 Second Edition, or Windows Millennium Edition ended on July 11, 2006. I am still using one of these operating systems; what should I do?
Windows 98, Windows 98 Second Edition, and Windows Millennium Edition have reached the end of their support life cycles. It should be a priority for customers who have these operating system versions to migrate to supported versions to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit the following Microsoft Support Lifecycle Web site. For more information about the extended security update support period for these operating system versions, visit the Microsoft Product Support Services Web site.

Extended security update support for Microsoft Windows NT Workstation 4.0 Service Pack 6a and Windows 2000 Service Pack 2 ended on June 30, 2004. Extended security update support for Microsoft Windows NT Server 4.0 Service Pack 6a ended on December 31, 2004. Extended security update support for Microsoft Windows 2000 Service Pack 3 ended on June 30, 2005. I am still using one of these operating systems; what should I do?
Windows NT Workstation 4.0 Service Pack 6a, Windows NT Server 4.0 Service Pack 6a, Windows 2000 Service Pack 2, and Windows 2000 Service Pack 3 have reached the end of their support life cycles. It should be a priority for customers who have these operating system versions to migrate to supported versions to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit the following Microsoft Support Lifecycle Web site. For more information about the extended security update support period for these operating system versions, visit the Microsoft Product Support Services Web site.

Customers who require custom support for these products must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an Alliance, Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, visit the Microsoft Worldwide Information Web site, select the country, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Windows Operating System Product Support Lifecycle FAQ.

Can I use the Microsoft Baseline Security Analyzer (MBSA) to determine whether this update is required?
The following table provides the MBSA detection summary for this security update.
Software MBSA 1.2.1 MBSA 2.0

Microsoft Windows 2000 Service Pack 4


Yes


Yes

Microsoft Windows XP Service Pack 2


Yes


Yes

Microsoft Windows XP Professional x64 Edition


No


Yes

Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1


Yes


Yes

Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with Service Pack 1 for Itanium-based Systems


No


Yes

Microsoft Windows Server 2003 x64 Edition family


No


Yes

For more information about MBSA, visit the MBSA Web site. For more information about the programs that Microsoft Update and MBSA 2.0 currently do not detect, see Microsoft Knowledge Base Article 895660.

For more detailed information, see Microsoft Knowledge Base Article 910723.

Can I use Systems Management Server (SMS) to determine whether this update is required?
The following table provides the SMS detection summary for this security update.
Software SMS 2.0 SMS 2003

Microsoft Windows 2000 Service Pack 4


Yes


Yes

Microsoft Windows XP Service Pack 2


Yes


Yes

Microsoft Windows XP Professional x64 Edition


No


Yes

Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1


Yes


Yes

Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with Service Pack 1 for Itanium-based Systems


No


Yes

Microsoft Windows Server 2003 x64 Edition family


No


Yes

SMS 2.0 and SMS 2003 Software Update Services (SUS) Feature Pack can use MBSA 1.2.1 for detection and therefore have the same limitation that is listed earlier in this bulletin related to programs that MBSA 1.2.1 does not detect.

For SMS 2.0, the SMS SUS Feature Pack, which includes the Security Update Inventory Tool (SUIT), can be used by SMS to detect security updates. SMS SUIT uses the MBSA 1.2.1 engine for detection. For more information about SUIT, visit the following Microsoft Web site. For more information about the limitations of SUIT, see Microsoft Knowledge Base Article 306460. The SMS SUS Feature Pack also includes the Microsoft Office Inventory Tool to detect required updates for Microsoft Office applications.

For SMS 2003, the SMS 2003 Inventory Tool for Microsoft Updates (ITMU) can be used by SMS to detect security updates that are offered by Microsoft Update and that are supported by Windows Server Update Services. For more information about the SMS 2003 ITMU, visit the following Microsoft Web site. SMS 2003 can also use the Microsoft Office Inventory Tool to detect required updates for Microsoft Office applications.

For more information about SMS, visit the SMS Web site.

For more detailed information, see Microsoft Knowledge Base Article 910723.
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Vulnerability Details

HTML Help ActiveX Control Vulnerability - CVE-2007-0214

A remote code execution vulnerability exists in the HTML Help ActiveX control. An attacker could exploit the vulnerability by constructing a specially crafted Web page that could potentially allow remote code execution if a user visited that page. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

Mitigating Factors for HTML Help ActiveX Control Vulnerability - CVE-2007-0214:


By default, all supported versions of Microsoft Outlook and Microsoft Outlook Express open HTML e-mail messages in the Restricted sites zone. The Restricted sites zone helps reduce attacks that could try to exploit this vulnerability by preventing Active Scripting and ActiveX controls from being used when reading HTML e-mail. However, if a user clicks on a link within an e-mail they could still be vulnerable to this issue through the Web-based attack scenario.


By default, Internet Explorer on Windows Server 2003 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that have not been added to Internet Explorer Trusted sites zone.
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Workarounds for HTML Help ActiveX Control Vulnerability - CVE-2007-0214:

Microsoft has tested the following workarounds. Although these workarounds will not correct the underlying vulnerability, they help block known attack vectors. When a workaround reduces functionality, it is identified in the following section.


Temporarily prevent the HTML Help ActiveX control from running in Internet Explorer

To protect against this vulnerability, set the kill bit for the ActiveX control to
temporarily disable the HTML Help ActiveX and keep it from running in Internet Explorer.
Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use the Registry Editor at your own risk.

The CLSID for an ActiveX control is a GUID for that control. You can prevent an ActiveX control from running in Internet Explorer by setting the kill bit so that the control is never called by Internet Explorer. The kill bit is a specific value for the Compatibility Flags DWORD value for the ActiveX control in the registry.

The CLSID for the HTML Help ActiveX control is {52a2aaae-085d-4187-97ea-8c30db990436}

For detailed steps about stopping an ActiveX control from running in Internet Explorer, see Microsoft Knowledge Base Article 240797. Follow these steps and create a Compatibility Flags value in the registry to prevent the HTML Help ActiveX control from being instantiated in Internet Explorer.

Note If you use this workaround you must reset this registry change by removing the same Compatibility Flags registry value. You should do this after you have applied this security update to regain normal functionality supplied by the HTML Help ActiveX control.

Impact of Workaround: Disabling the HTML Help ActiveX control prevents Internet Explorer from instantiating the control. This configuration causes program compatibility issues. Some examples of such issues are:


In Help and Support Center, the Index feature no longer works.


In HTML Help, features such as Related Topics and Shortcuts no longer work.

Features that are provided by the HTML Help control in Enterprise intranet programs no longer work.
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FAQ for HTML Help ActiveX Control Vulnerability - CVE-2007-0214:

What is the scope of the vulnerability?
This vulnerability could allow remote code execution. If a user is logged on with administrative privileges, 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 privileges. Users whose accounts are configured to have fewer privileges on the system could be less impacted than users who operate with administrative privileges.

What causes the vulnerability?
HTML Help ActiveX control methods do not perform sufficient parameter validation.

What is HTML Help and HTML Help ActiveX control?
Microsoft HTML Help is the standard help system for the Windows platform. HTML Help ActiveX control is a program (Hhctrl.ocx) that is used to insert help navigation and secondary window functionality into an HTML file. HTML Help ActiveX control is designed to work with Internet Explorer and the Shdocvw.dll component. The Shdocvw.dll exposes interfaces to its host to allow it to be hosted separately as an ActiveX control. The Shdocvw.dll component is more frequently referred to as the WebBrowser Control. For more information about the HTML Help ActiveX control, see the product documentation and HTML HELP API support.

What are Internet Explorer security zones?
Internet Explorer security zones are part of a system that divides online content into categories or zones that are based on the trustworthiness of the content. Specific Web domains can be assigned to a zone, depending on how much you trust the content of each domain. The zone then restricts the capabilities of the Web content, based on the zone's policy. By default, most Internet domains are treated as part of the Internet zone. By default, the policy of the Internet zone prevents scripts and other active code from accessing resources on the local system.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code on a users system. This could allow an attacker to take complete control of the affected system.

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 and then persuade a user to view the Web site. This can also include Web sites that accept user-provided content or advertisements, Web sites that host user-provided content or advertisements, and compromised Web sites. These Web sites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, an attacker would have to persuade 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?
This vulnerability requires that a user view Web sites for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as users’ workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer on Windows Server 2003. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003 runs in a restricted mode that is known as Enhanced Security Configuration. This mode sets the security level for the Internet zone to High. This is a mitigating factor for Web sites that have not been added to Internet Explorer Trusted sites zone. See the FAQ section of this security update for more information about Internet Explorer Enhanced Security Configuration.

What is the Internet Explorer Enhanced Security Configuration?
Internet Explorer Enhanced Security Configuration is a group of preconfigured Internet Explorer settings that reduce the likelihood of a user or of an administrator downloading and running specially crafted Web content on a server. Internet Explorer Enhanced Security Configuration reduces this risk by modifying many security-related settings. This includes the settings on the Security tab and the Advanced tab in the Internet Options dialog box. Some of the important modifications include the following:


Security level for the Internet zone is set to High. This setting disables scripts, ActiveX controls, Microsoft Java Virtual Machine (MSJVM), and file downloads.


Automatic detection of intranet sites is disabled. This setting assigns all intranet Web sites and all Universal Naming Convention (UNC) paths that are not explicitly listed in the Local intranet zone to the Internet zone.


Install On Demand and non-Microsoft browser extensions are disabled. This setting prevents Web pages from automatically installing components and prevents non-Microsoft extensions from running.


Multimedia content is disabled. This setting prevents music, animations, and video clips from running.

What does the update do?
The update removes the vulnerability by initializing parameters for HTML Help ActiveX control methods.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
No. When the security bulletin was released, Microsoft had not received information that this vulnerability was being exploited.

Acknowledgments

Microsoft thanks the following for working with us to help protect customers:


HD Moore of BreakingPoint Systems for working with Microsoft on the HTML Help Vulnerability (CVE-2007-0214).


Revisions:


V1.0 (February 13, 2007): Bulletin published.

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