Security Bulletin

Microsoft Security Bulletin MS07-027 - Critical

Published: May 08, 2007 | Updated: October 10, 2007

Version: 1.4

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 details.

Caveats: Microsoft Knowledge Base Article 931768 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 931768.

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 and Windows XP Professional x64 Edition Service Pack 2
• Microsoft Windows Server 2003 Service Pack 1 and Microsoft Windows Server 2003 Service Pack 2
• Microsoft Windows Server 2003 with SP1 for Itanium-based Systems and Microsoft Windows Server 2003 with SP2 for Itanium-based Systems
• Microsoft Windows Server 2003 x64 Edition and Microsoft Windows Server 2003 x64 Edition Service Pack 2
• Windows Vista
• Windows Vista x64 Edition

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 and Windows XP Professional x64 Edition Service Pack 2 — Download the update
• Microsoft Internet Explorer 6 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 — Download the update
• Microsoft Internet Explorer 6 for Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems — Download the update
• Microsoft Internet Explorer 6 for Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2 — 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 and Windows XP Professional x64 Edition Service Pack 2 — Download the update
• Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 — Download the update
• Windows Internet Explorer 7 for Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems — Download the update
• Windows Internet Explorer 7 for Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2 — Download the update
• Windows Internet Explorer 7 in Windows Vista — Download the update
• Windows Internet Explorer 7 in Windows Vista x64 Edition — Download the update

The software in this list has been tested to determine whether the versions are affected. Other versions are either past their support life cycle or are not affected. To determine the support life cycle for your product and version, visit the Microsoft Support Lifecycle Web site.

Executive Summary:

This update resolves several newly discovered, privately reported and public 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 the same user rights as the logged-on 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.

We recommend that customers apply the update immediately.

Severity Ratings and Vulnerability Identifiers:

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 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 XP Professional x64 Edition Service Pack 2 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 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 Service Pack 1 severity rating.
• The Internet Explorer 6 for Windows Server 2003 with SP2 for Itanium-based Systems and Windows Server 2003 x64 Edition Service Pack 2 severity rating is the same as the Internet Explorer 6 for Windows Server 2003 Service Pack 2 severity rating.
• The Windows Internet Explorer 7 for Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2 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 SP1 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.
• The Windows Internet Explorer 7 for Windows Server 2003 with SP2 for Itanium-based Systems and Windows Server 2003 x64 Edition Service Pack 2 severity rating is the same as the Internet Explorer 7 for Windows Server 2003 Service Pack 2 severity rating.
• The Windows Internet Explorer 7 in Windows Vista x64 Edition severity rating is the same as the Windows Internet Explorer 7 in Windows Vista severity rating.

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 several prior security updates. The most recent security bulletin ID and affected operating systems are listed in the following table.

What are the known issues that customers may experience when they install this security update?
Microsoft Knowledge Base Article 931768 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 931768.

Known issues since original release of the bulletin: :

• 937409: The “File Download - Security Warning” dialog box opens when you try to open Internet Explorer 7

Does this update contain any security-related changes that are not Internet Explorer specific?
Yes. The changes are listed in the “Vulnerability Details” section of this bulletin as the “Arbitrary File Rewrite Vulnerability - CVE-2007-2221”. The Microsoft ActiveX Control discussed there is no longer supported.

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 the following security update:

This update includes killbits that will prevent the following ActiveX controls from being run in Internet Explorer:

• This security update sets a killbit for the ActiveX control LaunchApp Software, available from Acer Incorporated. Acer Incorporated has released a security bulletin and an update that addresses a vulnerability in the effected component. For more information and download locations, see the security bulletin from Acer Incorporated. This kill bit is being set at the request of the owner of the ActiveX controls. The class identifier (CLSID) for this ActiveX control is:
  • {D9998BD0-7957-11D2-8FED-00606730D3AA}
• This security update sets a killbit for an ActiveX control developed by Research In Motion (RIM). Research In Motion (RIM) has released a security bulletin and an update that addresses a vulnerability in the effected component. For more information and download locations, see the security bulletin from Research In Motion. This kill bit is being set at the request of the owner of the ActiveX controls. The class identifier (CLSID) for this ActiveX control is:
  • {1D95A7C7-3282-4DB7-9A48-7C39CE152A19}

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.

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

Note for Windows Vista Microsoft does not support installing MBSA 2.0.1 on computers that run Windows Vista, but you may install MBSA 2.0.1 on a supported operating system and then scan the Windows Vista-based computer remotely. For additional information about MBSA support for Windows Vista, visit the MBSA Web site. See also Microsoft Knowledge Base Article 931943: Microsoft Baseline Security Analyzer (MBSA) support for Windows Vista.

For more detailed information, see Microsoft Knowledge Base Article 910723: Summary list of monthly detection and deployment guidance articles.

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.

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: Summary list of monthly detection and deployment guidance articles.

I am using an older version of the software discussed in this security bulletin; what should I do?
The affected software listed in this bulletin has been tested to determine whether the versions are affected. Other versions are past their support life cycle. To determine the support life cycle for your product and version, visit the Microsoft Support Lifecycle Web site.

It should be a priority for customers who have older versions of the software 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 older software 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.

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 visited the Web page. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

• 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 convince 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.

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:

  1. In Internet Explorer, click Internet Options on the Tools menu.
  2. Click the Security tab.
  3. Click Internet, and then click Custom Level.
  4. 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.
  5. Click Local intranet, and then click Custom Level.
  6. 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.
  7. Click OK two times to return to Internet Explorer.

  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:

  1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.
  2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.
  3. 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.
  4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.
  5. Repeat these steps for each site that you want to add to the zone.
  6. 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.

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”.

• 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:

  1. On the Internet Explorer Tools menu, click Internet Options.
  2. In the Internet Options dialog box, click the Security tab, and then click the Internet icon.
  3. 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.

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:

1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.
2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.
3. 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.
4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.
5. Repeat these steps for each site that you want to add to the zone.
6. 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.

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”.

• 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.

Note 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-2007-0942” section. Replace {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} below with the Class Identifiers found in this section.

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.

Impact of Workaround: There is no impact as long as the COM object is not intended to be used in Internet Explorer.

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.

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 convince 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 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?
This vulnerability requires that a user be logged on and visit 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:

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-2007-0942.

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.

A remote code execution vulnerability exists in the way Internet Explorer accessing a object when it is not initiated or already deleted. An attacker could exploit the vulnerability by constructing a specially crafted Web page. If a user viewed the Web page, the vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

• 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, compromised Web sites and Web sites that accept or host user-provided content or advertisements 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 convince 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.
• The Restricted sites zone helps reduce attacks that could try to exploit this vulnerability by preventing Active Scripting from being used when reading HTML e-mail messages. However, if a user clicks a link in an e-mail message, the user 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 section of this security update for more information about Internet Explorer Enhanced Security Configuration.

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.

• Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone
  You can help protect against this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

  1. In Internet Explorer, click Internet Options on the Tools menu.
  2. Click the Security tab.
  3. Click Internet, and then click Custom Level.
  4. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.
  5. Click Local intranet, and then click Custom Level.
  6. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.
  7. Click OK two times to return to Internet Explorer.

Note Disabling Active Scripting in the Internet and Local intranet security zones 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.

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: 1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab. 2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites. 3. 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. 4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add. 5. Repeat these steps for each site that you want to add to the zone. 6. 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.

Impact of Workaround: There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting 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 Active Scripting. 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”.

• 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:

  1. On the Internet Explorer Tools menu, click Internet Options.
  2. In the Internet Options dialog box, click the Security tab, and then click the Internet icon.
  3. 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.

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: 1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab. 2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites. 3. 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. 4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add. 5. Repeat these steps for each site that you want to add to the zone. 6. 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.

Impact of Workaround: There are side effects to prompting before running ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting 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 or Active Scripting 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 or Active Scripting. 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”.

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.

What causes the vulnerability?
Internet Explorer attempts to access an object which has been deleted. As a result, memory may be corrupted in such a way that an attacker could execute arbitrary code in the context of the logged-in user.

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?
An attacker could host a specially crafted Web site that is designed to exploit these vulnerabilities through Internet Explorer and then convince a user to visit 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 these vulnerabilities. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, 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 message 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 be logged on and visit 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 these vulnerabilities.

I am running Internet Explorer on Windows Server 2003. Does this mitigate these vulnerabilities?
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.

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.

For more information regarding Internet Explorer Enhanced Security Configuration, see the guide, Managing Internet Explorer Enhanced Security Configuration, at the following Web site.

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.

What does the update do?
The update removes the vulnerability by modifying the way that Internet Explorer handles errors when calls are made to objects that are no longer initialized.

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.

A remote code execution vulnerability exists in the way Internet Explorer handles a property method. 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.

• 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, compromised Web sites and Web sites that accept or host user-provided content or advertisements 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 convince 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. 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.
• Microsoft Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service Pack 4 is not affected by this vulnerability.

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.

• Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone
  You can help protect against this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

  1. In Internet Explorer, click Internet Options on the Tools menu.
  2. Click the Security tab.
  3. Click Internet, and then click Custom Level.
  4. Under Settings, in the Scripting section, under Active Scripting, click Promptor Disable, and then click OK.
  5. Click Local intranet, and then click Custom Level.
  6. Under Settings, in the Scripting section, under Active Scripting, click Promptor Disable, and then click OK.
  7. Click OK two times to return to Internet Explorer.

  Note Disabling Active Scripting in the Internet and Local intranet security zones 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.

  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:

  1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.
  2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.
  3. 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.
  4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.
  5. Repeat these steps for each site that you want to add to the zone.
  6. 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.

Impact of Workaround: There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting 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 Active Scripting. 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”.

• 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 and Active Scripting. You can do this by setting your browser security to High.

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

  1. On the Internet Explorer Tools menu, click Internet Options.
  2. In the Internet Options dialog box, click the Security tab, and then click the Internet icon.
  3. 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.

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: 1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab. 2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites. 3. 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. 4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add. 5. Repeat these steps for each site that you want to add to the zone. 6. 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.

Impact of Workaround: There are side effects to prompting before running ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting 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 or Active Scripting 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 or Active Scripting. 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”

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.

What causes the vulnerability?
When Internet Explorer calls the property method it may corrupt 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?
An attacker could host a specially crafted Web site that is designed to exploit the vulnerability and then convince 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 these vulnerabilities. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, 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 message 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 a user to be logged on and visiting 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 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.

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.

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.

For more information regarding Internet Explorer Enhanced Security Configuration, see the guide, Managing Internet Explorer Enhanced Security Configuration, at the following Web site.

What does the update do?
The update removes the vulnerability by modifying the way that Internet Explorer handles the property method.

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.

Several remote code execution vulnerabilities exist in Internet Explorer due to attempts to access uninitialized memory in certain situations. An attacker could exploit these vulnerabilities by constructing a specially crafted Web page. If a user viewed the Web page, these vulnerabilities could allow remote code execution. An attacker who successfully exploited these vulnerabilities could take complete control of an affected system.

• In a Web-based attack scenario, an attacker could host a Web site that contains a Web page that is used to exploit these vulnerabilities. In addition, compromised Web sites and Web sites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit these vulnerabilities. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, 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 Instant Messenger message that takes users to the attacker's Web site.
• 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.
• 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 these vulnerabilities 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. It cannot be ruled out that these vulnerabilities could be used in an exploit without Active Scripting. However, using Active Scripting significantly increases the chances of a successful exploit. As a result, these vulnerabilities have been given a severity rating of Critical on Windows Server 2003.

Microsoft has tested the following workarounds. Although these workarounds will not correct the underlying vulnerabilities, 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 Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone
  You can help protect against this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, follow these steps:

  1. In Internet Explorer, click Internet Options on the Tools menu.
  2. Click the Security tab.
  3. Click Internet, and then click Custom Level.
  4. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.
  5. Click Local intranet, and then click Custom Level.
  6. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.
  7. Click OK two times to return to Internet Explorer.

  Note Disabling Active Scripting in the Internet and Local intranet security zones 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.

  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:

  1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.
  2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.
  3. 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.
  4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add.
  5. Repeat these steps for each site that you want to add to the zone.
  6. 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.

  Impact of Workaround: There are side effects to prompting before running Active Scripting. Many Web sites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting 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 Active Scripting. 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”.

• 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:

  1. On the Internet Explorer Tools menu, click Internet Options.
  2. In the Internet Options dialog box, click the Security tab, and then click the Internet icon.
  3. 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.

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: 1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab. 2. In the Select a Web content zone to specify its current security settings box, click Trusted Sites, and then click Sites. 3. 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. 4. In the Add this Web site to the zone box, type the URL of a site that you trust, and then click Add. 5. Repeat these steps for each site that you want to add to the zone. 6. 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.

Impact of Workaround: There are side effects to prompting before running ActiveX Controls and Active Scripting. Many Web sites that are on the Internet or on an intranet use ActiveX or Active Scripting 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 or Active Scripting 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 or Active Scripting. 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”.

What is the scope of the vulnerabilities?
These are remote code execution vulnerabilities. An attacker who successfully exploited these vulnerabilities could remotely take complete control of an affected system. An attacker could then install programs; view, change, or delete data.

What causes the vulnerability?
Internet Explorer attempts to access uninitialized memory. As a result, memory may be corrupted in such a way that an attacker could execute arbitrary code in the context of the logged-in user.

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?
An attacker could host a specially crafted Web site that is designed to exploit these vulnerabilities through Internet Explorer and then convince 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 these vulnerabilities. In all cases, however, an attacker would have no way to force users to visit these Web sites. Instead, 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 message 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?
These vulnerabilities require 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 these vulnerabilities.

I am running Internet Explorer on Windows Server 2003. Does this mitigate these vulnerabilities?
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.

Note It cannot be ruled out that these vulnerabilities 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.

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.

For more information regarding Internet Explorer Enhanced Security Configuration, see the guide, Managing Internet Explorer Enhanced Security Configuration, at the following Web site.

What does the update do?
The update removes the vulnerabilities by modifying the way that Internet Explorer handles the error resulting in the exploitable condition.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about these vulnerabilities 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 these vulnerabilities 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.

A remote code execution vulnerability exists in a media service component that was never supported 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 visited the Web page. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

• 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 convince 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.
• 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.

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.

• Prevent 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.

Note The Class Identifiers and corresponding files where the COM objects are contained are documented under “What does the update do?” in the “FAQ for Arbitrary File Rewrite Vulnerability - CVE-2007-2221” section. Replace {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX} below with the Class Identifiers found in this section.

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.

Impact of Workaround: There is no impact as long as the COM object is not intended to be used in Internet Explorer.

• Uninstall Windows Media Server 4.1
  Remove Windows Media Server 4.1 from systems that it is not intended to run on

Impact of Workaround: Windows Media Server 4.1 functionality will no longer be accessible

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.

What causes the vulnerability?
An arbitrary file rewrite vulnerability exist in the control named "mdsauth.dll" of Microsoft Windows Media Server.

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 convince 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 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?
This vulnerability requires that a user be logged on and visit 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.

What does the update do?
This update sets the kill bit for a list the Class Identifier (CLSIDs)

The Class Identifies and corresponding files are as follows:

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.

Affected Software:

For information about the specific security update for your affected software, click the appropriate link:

Prerequisites For Windows 2000, this security update requires Service Pack 4 (SP4). For Small Business Server 2000, this security update requires Small Business Server 2000 Service Pack 1a (SP1a) or Small Business Server 2000 running with Windows 2000 Server Service Pack 4 (SP4).

The software that is listed 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.

For more information about how to obtain the latest service pack, see Microsoft Knowledge Base Article 260910.

Inclusion in Future Service Packs The update for this issue may be included in a future Update Rollup.

Installation Information

This security update supports the following setup switches.

Note You can combine these switches into one command. For backward compatibility, the security update also supports the setup switches that the earlier version of the Setup program uses. For more information about the supported installation switches, see Microsoft Knowledge Base Article 262841. For more information about the Update.exe installer, visit the Microsoft TechNet Web site. For more information about the terminology that appears in this bulletin, such as hotfix, see Microsoft Knowledge Base Article 824684.

Deployment Information

To install the security update without any user intervention, use one of the following commands at a command prompt for Windows 2000 Service Pack 4.

Internet Explorer 5.01 Service Pack 4:

IE5.01sp4-KB931768-Windows2000sp4-x86-enu /quiet

Internet Explorer 6.0 Service Pack 1:

IE6.0sp1-KB931768-Windows2000-x86-enu /quiet

Note Use of the /quiet switch will suppress all messages. This includes suppressing failure messages. Administrators should use one of the supported methods to verify the installation was successful when they use the /quiet switch. Administrators should also review the KB931768-IE501SP4-20070219.120000.log or KB931768-IE6SP1-20070219.120000.log files, respectively, for any failure messages when they use this switch.

To install the security update without forcing the system to restart, use one of the following commands at a command prompt for Windows 2000 Service Pack 4.

Internet Explorer 5.01 Service Pack 4:

IE5.01sp4-KB931768-Windows2000sp4-x86-enu /norestart

Internet Explorer 6.0 Service Pack 1:

IE6.0sp1-KB931768-Windows2000-x86-enu /norestart

For more information about how to deploy this security update with Software Update Services, visit the Software Update Services Web site. For more information about how to deploy this security update using Windows Server Update Services, visit the Windows Server Update Services Web site. This security update will also be available through the Microsoft Update Web site.

Restart Requirement

You must restart your system after you apply this security update.

Removal Information

To remove this security update, use the Add or Remove Programs tool in Control Panel.

System administrators can also use the Spuninst.exe utility to remove this security update. The Spuninst.exe utility is located in the %Windir%\$NTUninstallKB931768-IE501SP4-20070219.120000$\Spuninst and %Windir%\$NTUninstallKB931768-IE6SP1-20070219.120000$\Spuninst folders, respectively.

File Information

The English version of this security update has the file attributes that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service Pack 4 and on Small Business Server 2000:

Internet Explorer 6 Service Pack 1 on Windows 2000 Service Pack 4 and on Small Business Server 2000:

Verifying that the Update Has Been Applied

• Microsoft Baseline Security Analyzer
  To verify that a security update has been applied to an affected system, you can use the Microsoft Baseline Security Analyzer (MBSA) tool. MBSA allows administrators to scan local and remote systems for missing security updates and for common security misconfigurations. For more information about MBSA, visit the Microsoft Baseline Security Analyzer Web site.

• File Version Verification
  Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

1. Click Start, and then click Search.

2. In the Search Results pane, click All files and folders under Search Companion.

3. In the All or part of the file name box, type a file name from the appropriate file information table, and then click Search.

4. In the list of files, right-click a file name from the appropriate file information table, and then click Properties.

   Note Depending on the version of the operating system or programs installed, some of the files that are listed in the file information table may not be installed.

5. On the Version tab, determine the version of the file that is installed on your computer by comparing it to the version that is documented in the appropriate file information table.

   Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.

• Registry Key Verification
  You may also be able to verify the files that this security update has installed by reviewing the following registry key:

Internet Explorer 5.01 Service Pack 4 on Windows 2000 Service Pack 4 and on Small Business Server 2000:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Internet Explorer 5.01\SP4\KB931768-IE501SP4-20070219.120000\Filelist

Internet Explorer 6 Service Pack 1 on Windows 2000 Service Pack 4 and on Small Business Server 2000:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Internet Explorer 6\SP1\KB931768-IE6SP1-20070219.120000\Filelist

Note This registry key may not contain a complete list of installed files. Also, this registry key may not be created correctly when an administrator or an OEM integrates or slipstreams the 931768 security update into the Windows installation source files.

This security update requires Microsoft Windows XP Service Pack 2. For more information, see Microsoft Knowledge Base Article 322389: How to obtain the latest Windows XP service pack.

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

Inclusion in Future Service Packs The update for this issue will be included in a future service pack or update rollup.

Installation Information

This security update supports the following setup switches.

Note You can combine these switches into one command. For backward compatibility, the security update also supports the setup switches that the earlier version of the Setup program uses. For more information about the supported installation switches, see Microsoft Knowledge Base Article 262841. For more information about the Update.exe installer, visit the Microsoft TechNet Web site.

Deployment Information

To install the security update without any user intervention, use the following command at a command prompt for Microsoft Windows XP.

Internet Explorer 6 for Windows XP Service Pack 2:

Windowsxp-kb931768-x86-enu /quiet

Internet Explorer 7 for Windows XP Service Pack 2:

IE7-KB931768-WindowsXP-x86-enu /quiet

Note Use of the /quiet switch will suppress all messages. This includes suppressing failure messages. Administrators should use one of the supported methods to verify the installation was successful when they use the /quiet switch. Administrators should also review the KB931768.log or KB931768-IE7.log file for any failure messages when they use this switch.

To install the security update without forcing the system to restart, use the following command at a command prompt for Windows XP.

Internet Explorer 6 for Windows XP Service Pack 2:

Windowsxp-kb931768-x86-enu /norestart

Internet Explorer 7 for Windows XP Service Pack 2:

IE7-kb931768-WindowsXP-x86-enu /norestart

For information about how to deploy this security update by using Software Update Services, visit the Software Update Services Web site. For more information about how to deploy this security update using Windows Server Update Services, visit the Windows Server Update Services Web site. This security update will also be available through the Microsoft Update Web site.

Restart Requirement

You must restart your system after you apply this security update.

Removal Information

To remove this security update, use the Add or Remove Programs tool in Control Panel.

System administrators can also use the Spuninst.exe utility to remove this security update. The Spuninst.exe utility is located in the %Windir%\$NTUninstallKB931768$\Spuninst and %Windir%\ie7updates\KB931768-IE7\spuninst folders.

File Information

The English version of this security update has the file attributes that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Internet Explorer 6 for Windows XP Home Edition Service Pack 2, Windows XP Professional Service Pack 2, Windows XP Tablet PC Edition 2005, and Windows XP Media Center Edition 2005:

Internet Explorer 6 for Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2:

Internet Explorer 7 for Windows XP Home Edition Service Pack 2, Windows XP Professional Service Pack 2, Windows XP Tablet PC Edition 2005, and Windows XP Media Center Edition 2005:

Internet Explorer 7 for Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2:

Notes When you install these security updates, the installer checks to see if one or more of the files that are being updated on your system have previously been updated by a Microsoft hotfix.

If you have previously installed a hotfix to update one of these files, the installer copies the RTMQFE, SP1QFE, or SP2QFE files to your system. Otherwise, the installer copies the RTMGDR, SP1GDR, or SP2GDR files to your system. Security updates may not contain all variations of these files. For more information about this behavior, see Microsoft Knowledge Base Article 824994.

For more information about the Update.exe installer, visit the Microsoft TechNet Web site.

For more information about the terminology that appears in this bulletin, such as hotfix, see Microsoft Knowledge Base Article 824684.

Verifying that the Update Has Been Applied

• Microsoft Baseline Security Analyzer
  To verify that a security update has been applied to an affected system, you can use the Microsoft Baseline Security Analyzer (MBSA) tool. MBSA allows administrators to scan local and remote systems for missing security updates and for common security misconfigurations. For more information about MBSA, visit the Microsoft Baseline Security Analyzer Web site.

• File Version Verification
  Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

1. Click Start, and then click Search.

2. In the Search Results pane, click All files and folders under Search Companion.

3. In the All or part of the file name box, type a file name from the appropriate file information table, and then click Search.

4. In the list of files, right-click a file name from the appropriate file information table, and then click Properties.

   Note Depending on the version of the operating system or programs installed, some of the files that are listed in the file information table may not be installed.

5. On the Version tab, determine the version of the file that is installed on your computer by comparing it to the version that is documented in the appropriate file information table.

   Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.

• Registry Key Verification
  You may also be able to verify the files that this security update has installed by reviewing the following registry keys.

Internet Explorer 6 for Windows XP Home Edition Service Pack 2, Windows XP Professional Service Pack 2, Windows XP Tablet PC Edition 2005, and Windows XP Media Center Edition 2005:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP3\KB931768\Filelist

Internet Explorer 6 for Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP Version 2003\SP2\KB931768\Filelist

Internet Explorer 7 for Windows XP Home Edition Service Pack 2, Windows XP Professional Service Pack 2, Windows XP Tablet PC Edition 2005, and Windows XP Media Center Edition 2005:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP0\KB931768-IE7\Filelist

Internet Explorer 7 for Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP Version 2003\SP2\KB931768-IE7\Filelist

Note These registry keys may not contain a complete list of installed files. Also, these registry keys may not be created correctly if an administrator or an OEM integrates or slipstreams the 931768 security update into the Windows installation source files.

Prerequisites The security update for Internet Explorer 6 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 requires Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2.

The security update for Windows Internet Explorer 7 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2 requires Windows Server 2003 Service Pack 1 or Windows Server 2003 Service Pack 2.

Inclusion in Future Service Packs The update for this issue may be included in a future service pack or update rollup.

Installation Information

This security update supports the following setup switches.

Note You can combine these switches into one command. For backward compatibility, the security update also supports many of the setup switches that the earlier version of the Setup program uses. For more information about the supported installation switches, see Microsoft Knowledge Base Article 262841. For more information about the Update.exe installer, visit the Microsoft TechNet Web site.

Deployment Information

To install the security update without any user intervention, use the following command at a command prompt for Windows Server 2003.

Internet Explorer 6 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2:

Windowsserver2003-kb931768-x86-enu /quiet

Internet Explorer 7 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2:

IE7-KB931768-WindowsServer2003-x86-enu / quiet

Note Use of the /quiet switch will suppress all messages. This includes suppressing failure messages. Administrators should use one of the supported methods to verify the installation was successful when they use the /quiet switch. Administrators should also review the KB931768.log file for any failure messages when they use this switch.

To install the security update without forcing the system to restart, use the following command at a command prompt for Windows Server 2003.

Internet Explorer 6 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2:

Windowsserver2003-kb931768-x86-enu /norestart

Internet Explorer 7 for Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2:

IE7-KB931768-WindowsServer2003-x86-enu / norestart

For information about how to deploy this security update by using Software Update Services, visit the Software Update Services Web site. For more information about how to deploy this security update using Windows Server Update Services, visit the Windows Server Update Services Web site. This security update will also be available through the Microsoft Update Web site.

Restart Requirement

You must restart your system after you apply this security update.

This security update does not support HotPatching. For more information about HotPatching see Microsoft Knowledge Base Article 897341.

Removal Information

To remove this update, use the Add or Remove Programs tool in Control Panel.

System administrators can also use the Spuninst.exe utility to remove this security update. The Spuninst.exe utility is located in the %Windir%\$NTUninstallKB931768$\Spuninst folder.

File Information

The English version of this security update has the file attributes that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Internet Explorer 6 for Windows Server 2003, Web Edition with SP1; Windows Server 2003, Standard Edition with SP1; Windows Server 2003, Enterprise Edition with SP1; Windows Server 2003, Datacenter Edition with SP1; Windows Small Business Server 2003 with SP1; Windows Server 2003 R2, Web Edition; Windows Server 2003 R2, Standard Edition; Windows Server 2003 R2, Datacenter Edition; Windows Server 2003 R2, Enterprise Edition; Windows Small Business Server 2003 R2; Windows Server 2003, Web Edition with SP2; Windows Server 2003, Standard Edition with SP2; Windows Server 2003, Enterprise Edition with SP2; Windows Server 2003, Datacenter Edition with SP2; and Windows Small Business Server 2003 R2 with SP2:

Internet Explorer 6 for Windows Server 2003, Enterprise Edition with SP1 for Itanium-based Systems; Windows Server 2003, Datacenter Edition with SP1 for Itanium-based Systems; Windows Server 2003, Enterprise Edition with SP2 for Itanium-based Systems; and Windows Server 2003, Datacenter Edition with SP2 for Itanium-based Systems:

Internet Explorer 6 for Windows Server 2003, Standard x64 Edition with SP1; Windows Server 2003, Enterprise x64 Edition with SP1; and Windows Server 2003, Datacenter x64 Edition with SP1; Windows Server 2003 R2, Standard x64 Edition; Windows Server 2003 R2, Enterprise x64 Edition; Windows Server 2003 R2, Datacenter x64 Edition; Windows Server 2003 with SP2, Standard x64 Edition; Windows Server 2003 with SP2, Enterprise x64 Edition; and Windows Server 2003 with SP2, Datacenter x64 Edition:

Internet Explorer 7 for Windows Server 2003, Web Edition with SP1; Windows Server 2003, Standard Edition with SP1; Windows Server 2003, Enterprise Edition with SP1; Windows Server 2003, Datacenter Edition with SP1; Windows Small Business Server 2003 with SP1;Windows Server 2003 R2, Web Edition; Windows Server 2003 R2, Standard Edition; Windows Server 2003 R2, Datacenter Edition; Windows Server 2003 R2, Enterprise Edition; Windows Small Business Server 2003 R2; Windows Server 2003, Web Edition with SP2; Windows Server 2003, Standard Edition with SP2; Windows Server 2003, Enterprise Edition with SP2; Windows Server 2003, Datacenter Edition with SP2; and Windows Small Business Server 2003 R2 with SP2:

Internet Explorer 7 for Windows Server 2003, Enterprise Edition with SP1 for Itanium-based Systems; and Windows Server 2003, Datacenter Edition with SP1 for Itanium-based Systems; Windows Server 2003, Enterprise Edition with SP2 for Itanium-based Systems; and Windows Server 2003, Datacenter Edition with SP2 for Itanium-based Systems:

Internet Explorer 7 for Windows Server 2003, Standard x64 Edition with SP1; Windows Server 2003, Enterprise x64 Edition with SP1; and Windows Server 2003, Datacenter x64 Edition with SP1; Windows Server 2003 R2, Standard x64 Edition; Windows Server 2003 R2, Enterprise x64 Edition; Windows Server 2003 R2, Datacenter x64 Edition; Windows Server 2003 with SP2, Standard x64 Edition; Windows Server 2003 with SP2, Enterprise x64 Edition; and Windows Server 2003 with SP2, Datacenter x64 Edition:

Notes When you install these security updates, the installer checks to see if one or more of the files that are being updated on your system have previously been updated by a Microsoft hotfix.

If you have previously installed a hotfix to update one of these files, the installer copies the RTMQFE, SP1QFE, or SP2QFE files to your system. Otherwise, the installer copies the RTMGDR, SP1GDR, or SP2GDR files to your system. Security updates may not contain all variations of these files. For more information about this behavior, see Microsoft Knowledge Base Article 824994.

For more information about the Update.exe installer, visit the Microsoft TechNet Web site.

For more information about the terminology that appears in this bulletin, such as hotfix, see Microsoft Knowledge Base Article 824684.

Verifying that the Update Has Been Applied

• Microsoft Baseline Security Analyzer
  To verify that a security update has been applied to an affected system, you can use the Microsoft Baseline Security Analyzer (MBSA) tool. MBSA allows administrators to scan local and remote systems for missing security updates and for common security misconfigurations. For more information about MBSA, visit the Microsoft Baseline Security Analyzer Web site.

• File Version Verification
  Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

1. Click Start, and then click Search.

2. In the Search Results pane, click All files and folders under Search Companion.

3. In the All or part of the file name box, type a file name from the appropriate file information table, and then click Search.

4. In the list of files, right-click a file name from the appropriate file information table, and then click Properties.

   Note Depending on the version of the operating system or programs installed, some of the files that are listed in the file information table may not be installed.

5. On the Version tab, determine the version of the file that is installed on your computer by comparing it to the version that is documented in the appropriate file information table.

   Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.

• Registry Key Verification
  You may also be able to verify the files that this security update has installed by reviewing the following registry key.

Internet Explorer 6 for Windows Server 2003, Web Edition with SP1; Windows Server 2003, Standard Edition with SP1; Windows Server 2003, Enterprise Edition with SP1; Windows Server 2003, Datacenter Edition with SP1; Windows Small Business Server 2003 with SP1; Windows Server 2003 R2, Web Edition; Windows Server 2003 R2, Standard Edition; Windows Server 2003 R2, Datacenter Edition; Windows Server 2003 R2, Enterprise Edition; Windows Small Business Server 2003 R2; Windows Server 2003, Enterprise Edition for Itanium-based Systems; Windows Server 2003, Datacenter Edition for Itanium-based Systems; Windows Server 2003, Enterprise Edition with SP1 for Itanium-based Systems; Windows Server 2003, Datacenter Edition with SP1 for Itanium-based Systems; Windows Server 2003, Standard x64 Edition with SP1; Windows Server 2003, Enterprise x64 Edition with SP1; and Windows Server 2003, Datacenter x64 Edition with SP1; Windows Server 2003 R2, Standard x64 Edition; Windows Server 2003 R2, Enterprise x64 Edition; and Windows Server 2003 R2, Datacenter x64 Edition; Windows Server 2003, Web Edition with SP2; Windows Server 2003, Standard Edition with SP2; Windows Server 2003, Enterprise Edition with SP2; Windows Server 2003, Datacenter Edition with SP2; and Windows Small Business Server 2003 R2 with SP2:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows Server 2003\SP3\KB931768\Filelist

Internet Explorer 7 for Windows Server 2003, Web Edition with SP1; Windows Server 2003, Standard Edition with SP1; Windows Server 2003, Enterprise Edition with SP1; Windows Server 2003, Datacenter Edition with SP1; Windows Small Business Server 2003 with SP1; Windows Server 2003 R2, Web Edition; Windows Server 2003 R2, Standard Edition; Windows Server 2003 R2, Datacenter Edition; Windows Server 2003 R2, Enterprise Edition; Windows Small Business Server 2003 R2; Windows Server 2003, Enterprise Edition with SP1 for Itanium-based Systems; Windows Server 2003, Datacenter Edition with SP1 for Itanium-based Systems; Windows Server 2003, Standard x64 Edition with SP1; Windows Server 2003, Enterprise x64 Edition with SP1; and Windows Server 2003, Datacenter x64 Edition with SP1; Windows Server 2003 R2, Standard x64 Edition; Windows Server 2003 R2, Enterprise x64 Edition; and Windows Server 2003 R2, Datacenter x64 Edition; Windows Server 2003, Web Edition with SP2; Windows Server 2003, Standard Edition with SP2; Windows Server 2003, Enterprise Edition with SP2; Windows Server 2003, Datacenter Edition with SP2; and Windows Small Business Server 2003 R2 with SP2:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows Server 2003\SP0\KB931768-IE7\Filelist

Note This registry key may not contain a complete list of installed files. Also, this registry key may not be created correctly if an administrator or an OEM integrates or slipstreams the 931768 security update into the Windows installation source files.

Prerequisites This security update requires a released version of Windows Vista.

Inclusion in Future Service Packs The update for this issue will be included in a future service pack or update rollup.

Installation Information This security update supports the following setup switches.

Note For more information about the wusa.exe installer, see Microsoft Knowledge Base Article 934307.

Deployment Information

To install the security update without any user intervention, use the following command at a command prompt for Windows Vista:

Windows6.0-KB931768-x86.msu /quiet

Note Use of the /quiet switch will suppress all messages including failure messages. Administrators should use one of the supported methods to verify the installation was successful. Administrators should also review the system event logs for any failure messages when they use this switch.

To install the security update without forcing the system to restart, use the following command at a command prompt for Windows Vista:

Windows6.0-KB931768-x86.msu /quiet /norestart

For more information about how to deploy this security update using Windows Server Update Services, visit the Windows Server Update Services Web site. This security update will also be available through the Microsoft Update Web site.

Restart Requirement

You must restart your system after you apply this security update.

Removal Information

WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, click Security, then under Windows Update, click Viewinstalled updates and select from the list of updates.

File Information

This security update has the file attributes that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Windows Vista Ultimate, Windows Vista Enterprise, Windows Vista Business, Windows Vista Home Premium, Windows Vista Home Basic, and Windows Vista Starter:

64-bit editions of Windows Vista Ultimate, Windows Vista Enterprise, Windows Vista Business, Windows Vista Home Premium, Windows Vista Home Basic, and Windows Vista Starter:

Note When you install this security update, Windows checks to see if one or more of the files that are being updated on your system have previously been updated by a Windows hotfix. If you have previously installed a hotfix to update one of these files, the installer will apply the LDR version of this update. Otherwise, the installer will apply the GDR version of the update.

For more information about this behavior, see Microsoft Knowledge Base Article 824994.

For more information about the wusa.exe installer, see Microsoft Knowledge Base Article 934307.

For more information about the terminology that appears in this bulletin, such as hotfix, see Microsoft Knowledge Base Article 824684.

Verifying that the Update Has Been Applied

• Microsoft Baseline Security Analyzer
  To verify that a security update has been applied to an affected system, you may be able to use the Microsoft Baseline Security Analyzer (MBSA) tool. See the frequently asked question, “Can I use the Microsoft Baseline Security Analyzer (MBSA) to determine whether this update is required?” in the section, Frequently Asked Questions (FAQ) Related to This Security Update, earlier in this bulletin.

• File Version Verification

  Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

  1. Click Start and then enter an update file name in Start Search.
  2. When the file appears under Programs, right-click on the file name and click Properties.
  3. Under the General tab, compare the file size with the file information tables provided earlier in this section.
  4. You may also click on the Details tab and compare information, such as file version and date modified, with the file information tables provided earlier in this section.
  5. Finally, you may also click on the Previous Versions tab and compare file information for the previous version of the file with the file information for the new, or updated, version of the file.

Acknowledgments

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

• TippingPoint and the Zero Day Initiative for reporting the Uninitialized Memory Corruption Vulnerability - (CVE-2007-0944).
• JJ Reyes of Secunia Research for reporting the HTML Objects Memory Corruption Vulnerability - (CVE-2007-0947).
• Haifei Li of Fortinet's FortiGuard Global Security Research Team for reporting the Arbitrary File Rewrite Vulnerability - (CVE-2007-2221).

Obtaining Other Security Updates:

Updates for other security issues are available at the following locations:

• Security updates are available at the Microsoft Download Center. You can find them most easily by doing a keyword search for "security_patch."
• Updates for consumer platforms are available at the Microsoft Update Web site.

Support:

• Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.
• International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.

Security Resources:

• The Microsoft TechNet Security Web site provides additional information about security in Microsoft products.
• TechNet Update Management Center
• Microsoft Software Update Services
• Microsoft Windows Server Update Services
• Microsoft Baseline Security Analyzer (MBSA)
• Windows Update
• Microsoft Update
• Windows Update Catalog: For more information about the Windows Update Catalog, see Microsoft Knowledge Base Article 323166.
• Office Update

Software Update Services:

By using Microsoft Software Update Services (SUS), administrators can quickly and reliably deploy the latest critical updates and security updates to Windows 2000 and Windows Server 2003-based servers, and to desktop systems that are running Windows 2000 Professional or Windows XP Professional.

For more information about how to deploy security updates by using Software Update Services, visit the Software Update Services Web site.

Windows Server Update Services:

By using Windows Server Update Services (WSUS), administrators can quickly and reliably deploy the latest critical updates and security updates for Windows 2000 operating systems and later, Office XP and later, Exchange Server 2003, and SQL Server 2000 onto Windows 2000 and later operating systems.

For more information about how to deploy security updates using Windows Server Update Services, visit the Windows Server Update Services Web site.

Systems Management Server:

Microsoft Systems Management Server (SMS) delivers a highly configurable enterprise solution for managing updates. By using SMS, administrators can identify Windows-based systems that require security updates and can perform controlled deployment of these updates throughout the enterprise with minimal disruption to end users. For more information about how administrators can use SMS 2003 to deploy security updates, visit the SMS 2003 Security Patch Management Web site. SMS 2.0 users can also use Software Updates Service Feature Pack to help deploy security updates. For information about SMS, visit the SMS Web site.

Note SMS uses the Microsoft Baseline Security Analyzer, the Microsoft Office Detection Tool, and the Enterprise Update Scan Tool to provide broad support for security bulletin update detection and deployment. Some software updates may not be detected by these tools. Administrators can use the inventory capabilities of the SMS in these cases to target updates to specific systems. For more information about this procedure, visit the following Web site. Some security updates require administrative rights following a restart of the system. Administrators can use the Elevated Rights Deployment Tool (available in the SMS 2003 Administration Feature Pack and in the SMS 2.0 Administration Feature Pack) to install these updates.

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 (May 8, 2007): Bulletin published.
• V1.1 (May 8, 2007): Updated file version, size and time-stamp information for the Microsoft Internet Explorer 6 for Windows XP Service Pack 2.
• V1.2 (May 16, 2007): Bulletin revised due to an incorrect file name in Arbitrary File Rewrite Vulnerability - CVE-2007-2221 killbit table; A new issue discovered with the security update: 937409 The “File Download - Security Warning” dialog box opens when you try to open Internet Explorer 7;Updated file names for Internet Explorer 7
• V1.3 (June 6, 2007): Bulletin revised to remove the literal “Service Pack 1” from all instances of “Windows Server 2003 x64 Edition Service Pack 1”.
• V1.4 (October 10, 2007): Bulletin revised to include missing folder information for Internet Explorer 7 for Windows Server 2003.

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