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HistoryFeb 14, 2007 - 12:00 a.m.

Microsoft Security Bulletin MS07-016 Cumulative Security Update for Internet Explorer (928090)

2007-02-1400:00:00
vulners.com
22

Microsoft Security Bulletin MS07-016
Cumulative Security Update for Internet Explorer (928090)
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 several prior security updates. See the frequently asked questions (FAQ) section of this bulletin for the complete list.

Caveats: Microsoft Knowledge Base Article 928090 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues. For more information, see Microsoft Knowledge Base Article 928090.

Tested Software and Security Update Download Locations:

Affected Software:

Microsoft Windows 2000 Service Pack 4

Microsoft Windows XP Service Pack 2

Microsoft Windows XP Professional x64 Edition

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

Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based Systems

Microsoft Windows Server 2003 x64 Edition

Non-Affected Software:

Windows Vista

Tested Microsoft Windows Components:

Affected Components:

Microsoft Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service Pack 4 — Download the update

Microsoft Internet Explorer 6 Service Pack 1 when installed on Windows 2000 Service Pack 4 — Download the update

Microsoft Internet Explorer 6 for Windows XP Service Pack 2 — Download the update

Microsoft Internet Explorer 6 for Windows XP Professional x64 Edition — Download the update

Microsoft Internet Explorer 6 for Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1 — Download the update

Microsoft Internet Explorer 6 for Windows Server 2003 for Itanium-based Systems and Windows Server 2003 with SP1 for Itanium-based Systems — Download the update

Microsoft Internet Explorer 6 for Windows Server 2003 x64 Edition — Download the update

Windows Internet Explorer 7 for Windows XP Service Pack 2 — Download the update

Windows Internet Explorer 7 for Windows XP Professional x64 Edition — Download the update

Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1 — Download the update

Windows Internet Explorer 7 for Windows Server 2003 with SP1 for Itanium-based Systems — Download the update

Windows Internet Explorer 7 for Windows Server 2003 x64 Edition — Download the update

Non-Affected Components:

Windows Internet Explorer 7 in 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 two newly discovered, publicly and privately reported vulnerabilities. Each vulnerability is documented in its own subsection in the “Vulnerability Details” section of this bulletin.

If a user is logged on with administrative user rights, an attacker who successfully exploited the most severe of these vulnerabilities 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.

We recommend that customers apply the update immediately.

Severity Ratings and Vulnerability Identifiers:
Vulnerability Identifiers Impact of Vulnerability Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service Pack 4 Internet Explorer 6 Service Pack 1 when installed on Windows 2000 Service Pack 4 Internet Explorer 6 for Windows XP Service Pack 2 Internet Explorer 6 for Windows Server 2003 and Windows Server 2003 Service Pack 1 Windows Internet Explorer 7 for Windows XP Service Pack 2 Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1

COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697

Remote Code Execution

Critical

Critical

Critical

Moderate

Important

Low

COM Object Instantiation Memory Corruption Vulnerability - CVE-2007-0219

Remote Code Execution

Critical

Critical

Critical

Moderate

Important

Low

FTP Server Response Parsing Memory Corruption Vulnerability - CVE-2007-0217

Remote Code Execution

Critical

Critical

Critical

Critical

None

None

Aggregate Severity of All Vulnerabilities

Critical

Critical

Critical

Critical

Important

Low

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 The security updates for 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 Internet Explorer 6 for Windows XP Professional x64 Edition severity rating is the same as the Internet Explorer 6 for Windows XP Service Pack 2 severity rating.

The Internet Explorer 6 for Windows Server 2003 for Itanium-based Systems and Windows Server 2003 with SP1 for Itanium-based Systems, and Windows Server 2003 x64 Edition severity rating is the same as the Internet Explorer 6 for Windows Server 2003 severity rating.

The Windows Internet Explorer 7 for Windows XP Professional x64 Edition severity rating is the same as the Internet Explorer 7 for Windows XP Service Pack 2 severity rating.

The Windows Internet Explorer 7 for Windows Server 2003 with Service Pack 1 for Itanium-based Systems and Windows Server 2003 x64 Edition severity rating is the same as the Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1 severity rating.
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Frequently Asked Questions (FAQ) Related to This Security Update

Why does this update address several reported security vulnerabilities?
This update contains support for several vulnerabilities because the modifications that are required to address these issues are located in related files. Instead of having to install several updates that are almost the same, customers can install only this 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 Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service Pack 4 Internet Explorer 6 Service Pack 1 when installed on Windows 2000 Service Pack 4 Internet Explorer 6 for Windows XP Service Pack 2 Internet Explorer 6 for Windows Server 2003 and Windows Server 2003 Service Pack 1 Windows Internet Explorer 7 for Windows XP Service Pack 2 Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1

MS06-072

Replaced

Replaced

Replaced

Replaced

Not applicable

Not applicable

What are the known issues that customers may experience when they install this security update?
Microsoft Knowledge Base Article 928090 documents the currently known issues that customers may experience when they install this security update. The article also documents recommended solutions for these issues. For more information, see Microsoft Knowledge Base Article 928090.

Does this update contain any security-related changes to functionality?
Yes. Besides the changes that are listed in the “Vulnerability Details” section of this bulletin, this update includes a defense-in-depth change to Internet Explorer. This defense-in-depth change helps mitigate the vulnerability addressed in Microsoft Security Bulletin MS06-045. The changes are also included in Windows Internet Explorer 7. Also included are security-related changes that were introduced in previous Internet Explorer bulletins.

Additionally, this update sets the kill bit for ActiveX controls previously addressed in Microsoft Security Bulletins:

The WMI Object Broker ActiveX control that is addressed in Microsoft Security Bulletin MS06-073: Vulnerability in Visual Studio 2005 Could Allow Remote Code Execution (925674):

7F5B7F63-F06F-4331-8A26-339E03C0AE3D

Does this update contain any changes to functionality?
Yes. Besides the changes that are listed in the "Vulnerability Details" section of this bulletin, this update includes the following changes in security functionality:

This security update includes changes to the Windows Internet Explorer 7 Phishing Filter. These changes where first introduced in the update discussed in Microsoft Knowledge Base Article 928089: “The computer may respond very slowly as the Phishing Filter evaluates Web page contents in Internet Explorer 7”

Note The update discussed in Microsoft Knowledge Base Article 928089 was made available to Windows Vista customers as a recommended update on Windows Update and Microsoft Update on January 30, 2007.

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.
Product 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

Note MBSA 1.2.1 does not support systems with Windows Internet Explorer 7 installed. MBSA 2.0 does support systems with Windows Internet Explorer 7 installed.

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.
Product 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

COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697:

A remote code execution vulnerability exists in the way Internet Explorer instantiates COM objects that are not intended to be instantiated in Internet Explorer. An attacker could exploit the vulnerability by constructing a specially crafted Web page that could potentially allow remote code execution if a user viewed the Web page. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

Mitigating Factors for COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697:

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability In addition, Web sites that accept or host user-provided content, or compromised Web sites and advertisement servers could contain specially crafted content that could exploit this vulnerability. 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 Instant Messenger message that takes users to the attacker's Web site.

An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. 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.

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 the number of successful attacks that 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. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.

COM Objects not intended to be instantiated in Internet Explorer are not included in the default allow-list for ActiveX controls in Windows Internet Explorer 7. Customers who are running Windows Internet Explorer 7 with default settings are therefore not at risk unless these COM Objects have been activated through the ActiveX opt-in feature in the Internet Zone. Customers who are upgrading to Windows Internet Explorer 7 and have enabled these COM objects in previous versions of Internet Explorer will have them enabled in Windows Internet Explorer 7. For more information on the ActiveX Opt-in feature and how to add ActiveX controls to the pre-approved list, see the product documentation.

Windows Internet Explorer 7 in Windows Vista is not affected by this vulnerability.
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Workarounds for COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697:

Microsoft has tested the following workarounds. While 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.

Configure Internet Explorer to prompt before running ActiveX Controls or disable ActiveX Controls in the Internet and Local intranet security zone

You can help protect against this vulnerability by changing your Internet Explorer settings to prompt before running ActiveX controls. To do this, follow these steps:

In Internet Explorer, click Internet Options on the Tools menu.

Click the Security tab.

Click Internet, and then click Custom Level.

Under Settings, in the ActiveX controls and plug-ins section, under Run ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.

Click Local intranet, and then click Custom Level.

Under Settings, in the ActiveX controls and plug-ins section, under Run ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.

Click OK two times to return to Internet Explorer.

Impact of Workaround: There are side effects to prompting before running ActiveX controls. Many Web sites that are on the Internet or on an intranet use ActiveX to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX controls to provide menus, ordering forms, or even account statements. Prompting before running ActiveX controls is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run ActiveX controls. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone”.

Add sites that you trust to the Internet Explorer Trusted sites zone.

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

Repeat these steps for each site that you want to add to the zone.

Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your computer. Two in particular that you may want to add are ".windowsupdate.microsoft.com" and “.update.microsoft.com” (without the quotation marks). These are the sites that will host the update, and it requires an ActiveX Control to install the update.

Set Internet and Local intranet security zone settings to “High” to prompt before running ActiveX Controls and Active Scripting in these zones

You can help protect against this vulnerability by changing your settings for the Internet security zone to prompt before running ActiveX controls. You can do this by setting your browser security to High.

To raise the browsing security level in Microsoft Internet Explorer, follow these steps:

On the Internet Explorer Tools menu, click Internet Options.

In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of Workaround: There are side effects to prompting before running ActiveX controls. Many Web sites that are on the Internet or on an intranet use ActiveX to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX controls to provide menus, ordering forms, or even account statements. Prompting before running ActiveX controls is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run ActiveX controls. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone”.

Add sites that you trust to the Internet Explorer Trusted sites zone.

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

Repeat these steps for each site that you want to add to the zone.

Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your computer. Two in particular that you may want to add are ".windowsupdate.microsoft.com" and “.update.microsoft.com” (without the quotation marks). These are the sites that will host the update, and it requires an ActiveX Control to install the update.

Prevent COM objects from running in Internet Explorer

You can disable attempts to instantiate a COM object in Internet Explorer by setting the kill bit for the control in the registry.

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 Registry Editor at your own risk.

For detailed steps that you can use to prevent a control from running in Internet Explorer, see Microsoft Knowledge Base Article 240797. Follow these steps in this article to create a Compatibility Flags value in the registry to prevent a COM object from being instantiated in Internet Explorer.

To set the kill bit for a CLSID with a value of {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}, paste the following text in a text editor such as Notepad. Then, save the file by using the .reg file name extension.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{ XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX }]
"Compatibility Flags"=dword:00000400

You can apply this .reg file to individual systems by double-clicking it. You can also apply it across domains by using Group Policy. For more information about Group Policy, visit the following Microsoft Web sites:

Group Policy collection

What is Group Policy Object Editor?

Core Group Policy tools and settings

Note You must restart Internet Explorer for your changes to take effect.

The Class Identifiers and corresponding files where the COM objects are contained are documented under “What does the update do?” in the “FAQ for COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697” section.

Impact of Workaround: There is no impact as long as the COM object is not intended to be used in Internet Explorer.
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FAQ for COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697:

What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could remotely 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.

What causes the vulnerability?
When Internet Explorer tries to instantiate certain COM objects as ActiveX controls, the COM objects may corrupt the system state in such a way that an attacker could execute arbitrary code.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. 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 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 is logged on and visits a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Windows Internet Explorer 7. Does this mitigate this vulnerability?
Yes. Customers who are running Windows Internet Explorer 7 with default settings, are not at risk unless these COM Objects have been activated through the ActiveX opt-in feature in the Internet Zone. Customers who are upgrading to Windows Internet Explorer 7 and have enabled these COM objects in previous versions of Internet Explorer will have them enabled in Windows Internet Explorer 7. For more information on the ActiveX Opt-in feature and how to add ActiveX controls to the pre-approved list, see the product documentation.

Windows Internet Explorer 7 in Windows Vista is not affected by this vulnerability.

What is the ActiveX opt-in feature in Windows Internet Explorer 7?
Windows Internet Explorer 7 includes an ActiveX opt-in feature, which means that nearly all pre-installed ActiveX controls are off by default. Users are prompted by the Information Bar before they can instantiate a previously installed ActiveX control that has not yet been used on the Internet. This enables a user to permit or deny access on a control-by-control basis. For more information about this and other new features, see the Windows Internet Explorer 7 features page.

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 next FAQ in this section for more information about Internet Explorer Enhanced Security Configuration.

What is 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 administrator downloading and running malicious Web content on a server. Internet Explorer Enhanced Security Configuration reduces this threat by modifying numerous security-related settings, including Security and Advanced tab settings in Internet Options. Some of the key modifications include:

Security level for the Internet zone is set to High. This setting disables scripts, ActiveX components, Microsoft virtual machine (Microsoft VM) HTML content, 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.

For more information regarding Internet Explorer Enhanced Security Configuration, please consult the Managing Internet Explorer Enhanced Security Configuration guide, which can be found at the following Web site.

What does the update do?
Because not all COM objects are designed to be accessed through Internet Explorer, this update sets the kill bit for a list of Class Identifiers (CLSIDs) for COM objects that have been found to exhibit similar behavior to the COM Object Instantiation Memory Corruption Vulnerability that is addressed in Microsoft Security Bulletin MS05-054. To help protect customers, this update prevents these CLSIDs from being instantiated in Internet Explorer. For more information about kill bits, see Microsoft Knowledge Base Article 240797.

The Class Identifiers and corresponding files where the COM objects are contained are as follows:
Class Identifier File

DA56F851-D3C5-11D3-844C-00C04F7A06E5

Imjpcksid.dll

6E3197A3-BBC3-11D4-84C0-00C04F7A06E5

Imjpskdic.dll

When this security bulletin was issued, had this vulnerability been publicly disclosed?
Yes. This vulnerability has been publicly disclosed. It has been assigned Common Vulnerability and Exposure number CVE-2006-4697.

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.
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COM Object Instantiation Memory Corruption Vulnerability - CVE-2007-0219:

A remote code execution vulnerability exists in the way Internet Explorer instantiates COM objects that are not intended to be instantiated in Internet Explorer. An attacker could exploit the vulnerability by constructing a specially crafted Web page that could potentially allow remote code execution if a user viewed the Web page. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

Mitigating Factors for COM Object Instantiation Memory Corruption Vulnerability - CVE-2007-0219:

In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit this vulnerability. In addition, Web sites that accept or host user-provided content or compromised Web sites and advertisement servers could contain specially crafted content that could exploit this vulnerability. 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 Instant Messenger message that takes users to the attacker's Web site.

An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. 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.

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 the number of successful attacks that 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. See the FAQ subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.

COM Objects not intended to be instantiated in Internet Explorer are not included in the default allow-list for ActiveX controls in Windows Internet Explorer 7. Customers who are running Windows Internet Explorer 7 with default settings, are therefore not at risk unless these COM Objects have been activated through the ActiveX opt-in feature in the Internet Zone. Customers who are upgrading to Windows Internet Explorer 7 and have enabled these COM objects in previous versions of Internet Explorer will have them enabled in Windows Internet Explorer 7. For more information on the ActiveX Opt-in feature and how to add ActiveX controls to the pre-approved list, see the product documentation.

Windows Internet Explorer 7 in Windows Vista is not affected by this vulnerability.
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Workarounds for COM Object Instantiation Memory Corruption Vulnerability - CVE-2007-0219:

Microsoft has tested the following workarounds. While 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.

Configure Internet Explorer to prompt before running ActiveX Controls or disable ActiveX Controls in the Internet and Local intranet security zone

You can help protect against this vulnerability by changing your Internet Explorer settings to prompt before running ActiveX controls. To do this, follow these steps:

In Internet Explorer, click Internet Options on the Tools menu.

Click the Security tab.

Click Internet, and then click Custom Level.

Under Settings, in the ActiveX controls and plug-ins section, under Run ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.

Click Local intranet, and then click Custom Level.

Under Settings, in the ActiveX controls and plug-ins section, under Run ActiveX controls and plug-ins, click Prompt or Disable, and then click OK.

Click OK two times to return to Internet Explorer.

Impact of Workaround: There are side effects to prompting before running ActiveX controls. Many Web sites that are on the Internet or on an intranet use ActiveX to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX controls to provide menus, ordering forms, or even account statements. Prompting before running ActiveX controls is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run ActiveX controls. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone”.

Add sites that you trust to the Internet Explorer Trusted sites zone.

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

Repeat these steps for each site that you want to add to the zone.

Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your computer. Two in particular that you may want to add are ".windowsupdate.microsoft.com" and “.update.microsoft.com” (without the quotation marks). These are the sites that will host the update, and it requires an ActiveX Control to install the update.

Set Internet and Local intranet security zone settings to “High” to prompt before running ActiveX Controls and Active Scripting in these zones

You can help protect against this vulnerability by changing your settings for the Internet security zone to prompt before running ActiveX controls. You can do this by setting your browser security to High.

To raise the browsing security level in Microsoft Internet Explorer, follow these steps:

On the Internet Explorer Tools menu, click Internet Options.

In the Internet Options dialog box, click the Security tab, and then click the Internet icon.

Under Security level for this zone, move the slider to High. This sets the security level for all Web sites you visit to High.

Note If no slider is visible, click Default Level, and then move the slider to High.

Note Setting the level to High may cause some Web sites to work incorrectly. If you have difficulty using a Web site after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

Impact of Workaround: There are side effects to prompting before running ActiveX controls. Many Web sites that are on the Internet or on an intranet use ActiveX to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX controls to provide menus, ordering forms, or even account statements. Prompting before running ActiveX controls is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run ActiveX controls. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone”.

Add sites that you trust to the Internet Explorer Trusted sites zone.

After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted Web sites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

To do this, follow these steps:

In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.

Repeat these steps for each site that you want to add to the zone.

Click OK two times to accept the changes and return to Internet Explorer.

Note Add any sites that you trust not to take malicious action on your computer. Two in particular that you may want to add are ".windowsupdate.microsoft.com" and “.update.microsoft.com” (without the quotation marks). These are the sites that will host the update, and it requires an ActiveX Control to install the update.

Prevent COM objects from running in Internet Explorer

You can disable attempts to instantiate a COM object in Internet Explorer by setting the kill bit for the control in the registry.

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 Registry Editor at your own risk.

For detailed steps that you can use to prevent a control from running in Internet Explorer, see Microsoft Knowledge Base Article 240797. Follow these steps in this article to create a Compatibility Flags value in the registry to prevent a COM object from being instantiated in Internet Explorer.

To set the kill bit for a CLSID with a value of {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}, paste the following text in a text editor such as Notepad. Then, save the file by using the .reg file name extension.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{ XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX }]
"Compatibility Flags"=dword:00000400

You can apply this .reg file to individual systems by double-clicking it. You can also apply it across domains by using Group Policy. For more information about Group Policy, visit the following Microsoft Web sites:

Group Policy collection

What is Group Policy Object Editor?

Core Group Policy tools and settings

Note You must restart Internet Explorer for your changes to take effect.

The Class Identifiers and corresponding files where the COM objects are contained are documented under “What does the update do?” in the “FAQ for COM Object Instantiation Memory Corruption Vulnerability - CVE-2006-4697” section.

Impact of Workaround: There is no impact as long as the COM object is not intended to be used in Internet Explorer.
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FAQ for COM Object Instantiation Memory Corruption Vulnerability - CVE-2007-0219:

What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could remotely 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.

What causes the vulnerability?
When Internet Explorer tries to instantiate certain COM objects as ActiveX controls, the COM objects may corrupt the system state in such a way that an attacker could execute arbitrary code.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. 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 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 is logged on and visits a Web site for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Windows Internet Explorer 7. Does this mitigate this vulnerability?
Yes. Customers who are running Windows Internet Explorer 7 with default settings, are not at risk unless these COM Objects have been activated through the ActiveX opt-in feature in the Internet Zone. Customers who are upgrading to Windows Internet Explorer 7 and have enabled these COM objects in previous versions of Internet Explorer will have them enabled in Windows Internet Explorer 7. For more information on the ActiveX Opt-in feature and how to add ActiveX controls to the pre-approved list, see the product documentation.

Windows Internet Explorer 7 in Windows Vista is not affected by this vulnerability.

What is the ActiveX opt-in feature in Windows Internet Explorer 7?
Windows Internet Explorer 7 includes an ActiveX opt-in feature, which means that nearly all pre-installed ActiveX controls are off by default. Users are prompted by the Information Bar before they can instantiate a previously installed ActiveX control that has not yet been used on the Internet. This enables a user to permit or deny access on a control-by-control basis. For more information about this and other new features, see the Windows Internet Explorer 7 features page.

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 next FAQ in this section for more information about Internet Explorer Enhanced Security Configuration.

What is 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 administrator downloading and running malicious Web content on a server. Internet Explorer Enhanced Security Configuration reduces this threat by modifying numerous security-related settings, including Security and Advanced tab settings in Internet Options. Some of the key modifications include:

Security level for the Internet zone is set to High. This setting disables scripts, ActiveX components, Microsoft virtual machine (Microsoft VM) HTML content, 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.

For more information regarding Internet Explorer Enhanced Security Configuration, please consult the Managing Internet Explorer Enhanced Security Configuration guide, which can be found at the following Web site.

What does the update do?
Because not all COM objects are designed to be accessed through Internet Explorer, this update sets the kill bit for a list of Class Identifiers (CLSIDs) for COM objects that have been found to exhibit similar behavior to the COM Object Instantiation Memory Corruption Vulnerability that is addressed in Microsoft Security Bulletin MS05-054. To help protect customers, this update prevents these CLSIDs from being instantiated in Internet Explorer. For more information about kill bits, see Microsoft Knowledge Base Article 240797.

The Class Identifiers and corresponding files where the COM objects are contained are as follows:
Class Identifier File

75C11604-5C51-48B2-B786-DF5E51D10EC9

Msb1fren.dll

8422DAE3-9929-11CF-B8D3-004033373DA8

Htmlmm.ocx

8422DAE7-9929-11CF-B8D3-004033373DA8

Htmlmm.ocx

261F6572-578B-40A7-B72E-61B7261D9F0C

Blnmgrps.dll

E56CCB42-598C-462D-9AD8-4FD5B4498C5D

Blnmgrps.dll

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. 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.
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FTP Server Response Parsing Memory Corruption Vulnerability - CVE-2007-0217:

A remote code execution vulnerability exists in the way Internet Explorer interprets certain responses from FTP servers. An attacker could exploit the vulnerability by sending specially crafted FTP responses in an FTP session to the FTP client included in Internet Explorer. An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. 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.

Mitigating Factors for FTP Server Response Parsing Memory Corruption Vulnerability - CVE-2007-0217:

In a Web-based attack scenario, an attacker would have to host an FTP server that would return these specially crafted FTP server responses to exploit this vulnerability. An attacker would have no way to force users to visit the site with the FTP server. Instead, an attacker would have to persuade them to visit the site, typically by getting them to click a link in an e-mail message or Instant Messenger message that takes them to the attacker's site.

An attacker who successfully exploited this vulnerability could gain the same user rights as the local user. 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.

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.

Note It cannot be ruled out that this vulnerability could be used in an exploit without Active Scripting. However, using Active Scripting significantly increases the chances of a successful exploit. As a result, this vulnerability has been given a severity rating of Critical on Windows Server 2003.

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 subsection of this vulnerability section for more information about Internet Explorer Enhanced Security Configuration.
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Workarounds for FTP Server Response Parsing Memory Corruption Vulnerability - CVE-2007-0217:

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.

Read e-mail messages in plain text format if you are using Outlook 2002 or a later version, or Outlook Express 6 SP1 or a later version, to help protect yourself from the HTML e-mail attack vector.

Microsoft Outlook 2002 users who have applied Office XP Service Pack 1 or a later version and Microsoft Outlook Express 6 users who have applied Internet Explorer 6 Service Pack 1 or a later version can enable this setting and view e-mail messages that are not digitally signed or e-mail messages that are not encrypted in plain text only.

Digitally signed e-mail messages or encrypted e-mail messages are not affected by the setting and may be read in their original formats. For more information about how to enable this setting in Outlook 2002, see Microsoft Knowledge Base Article 307594.

For information about this setting in Outlook Express 6, see Microsoft Knowledge Base Article 291387.

Impact of Workaround: E-mail messages that are viewed in plain text format will not contain pictures, specialized fonts, animations, or other rich content. Additionally:

The changes are applied to the preview pane and to open messages.

Pictures become attachments so that they are not lost.

Because the message is still in Rich Text or HTML format in the store, the object model (custom code solutions) may behave unexpectedly.
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FAQ for FTP Server Response Parsing Memory Corruption Vulnerability - CVE-2007-0217:

What is the scope of the vulnerability?
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could remotely 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?
When Internet Explorer handles specially crafted FTP server responses it may corrupt system memory in such a way that an attacker could execute arbitrary code.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited these vulnerabilities could gain the same user rights as the local user. 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?
In a Web-based attack scenario, an attacker would have to host an FTP server that is used to attempt to exploit this vulnerability. An attacker would have no way to force users to visit an FTP server. Instead, an attacker would have to persuade them to visit the FTP server site, typically by getting them to click a link on a Web page, in an e-mail message, or in an Instant Messenger request that takes users to the attacker's Web site.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user is logged on and visits an FTP server using the FTP Client included in Internet Explorer for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from these vulnerabilities.

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 next FAQ in this section for more information about Internet Explorer Enhanced Security Configuration.

What is 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 administrator downloading and running malicious Web content on a server. Internet Explorer Enhanced Security Configuration reduces this threat by modifying numerous security-related settings, including Security and Advanced tab settings in Internet Options. Some of the key modifications include:

Security level for the Internet zone is set to High. This setting disables scripts, ActiveX components, Microsoft virtual machine (Microsoft VM) HTML content, 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.

For more information regarding Internet Explorer Enhanced Security Configuration, please consult the Managing Internet Explorer Enhanced Security Configuration guide, which can be found at the following Web site.

What does the update do?
The update removes the vulnerability by modifying the way Internet Explorer handles FTP server responses.

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. 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.

Acknowledgments

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

H D Moore of BreakingPoint Systems for reporting five class identifiers documented in the COM Object Instantiation Memory Corruption Vulnerability (CVE-2007-0219).

iDefense for reporting the FTP Server Response Parsing Memory Corruption Vulnerability (CVE-2007-0217).

Disclaimer:

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions:

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