Version: 1.2

This update resolves a publicly reported vulnerability. A remote code execution vulnerability exists in the way that the Windows shell handles specially crafted URIs that are passed to it. If the Windows shell did not sufficiently validate these URIs, an attacker could exploit this vulnerability and execute arbitrary code. Microsoft has only identified ways to exploit this vulnerability on systems using Internet Explorer 7. However, the vulnerability exists in a Windows file, Shell32.dll, which is included in all supported editions of Windows XP and Windows Server 2003.

This is a critical security update for all supported editions of Windows XP and Windows Server 2003. For more information, see the subsection, Affected and Non-Affected Software, in this section.

This security update addresses the vulnerability by changing the way that Windows shell handles invalid URIs. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

This security update also addresses the vulnerability first described in Microsoft Security Advisory 943521. For more information, see the FAQ subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. Microsoft recommends that customers apply the update immediately.

Known Issues. Microsoft Knowledge Base Article 943460 documents currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues.

The following software have been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

Affected Software

Non-Affected Software

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startA("s"+sID)Frequently Asked Questions (FAQ) Related to This Security UpdateendA()

What updates does this release replace?
This update replaces the update provided by MS06-045. This update does not replace the update provided by bulletin MS07-006 because the files that are updated in that bulletin do not replace all the files that are replaced by the update offered in bulletin MS06-045. Customers should install the updates offered from bulletins MS07-061 and MS07-006.

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 have been tested to determine which versions or editions are affected. Other versions or editions are past their support life cycle. To determine the support life cycle for your software version or edition, visit Microsoft Support Lifecycle.

It should be a priority for customers who have older versions or editions of the software to migrate to supported versions or editions to prevent potential exposure to vulnerabilities. For more information about the Windows Product Lifecycle, visit Microsoft Support Lifecycle. For more information about the extended security update support period for these software versions or editions, visit Microsoft Product Support Services.

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 Microsoft Worldwide Information, 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.

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startA("s"+sID)Severity Ratings and Vulnerability IdentifiersendA()

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startA("s"+sID)Windows URI Handling Vulnerability - CVE-2007-3896endA()

A remote code execution vulnerability exists in the way that the Windows shell handles specially crafted URIs that are passed to it. An attacker could exploit this vulnerability by including a specially crafted URI in an application or attachment, which could potentially allow remote code execution.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2007-3896.

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startA("s"+sID)Mitigating Factors for Windows URI Handling Vulnerability - CVE-2007-3896endA()

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

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startA("s"+sID)Workarounds for Windows URI Handling Vulnerability - CVE-2007-3896endA()

Microsoft has not identified any workarounds for this vulnerability.

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startA("s"+sID)FAQ for Windows URI Handling Vulnerability - CVE-2007-3896endA()

What is the scope of the vulnerability? 
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged on user.

If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

What causes the vulnerability? 
The Windows shell insufficiently handles invalid URIs.

What is a URI?
A Uniform Resource Identifier (URI) is a string of characters used to act on or identify resources from the Internet or over a network. A URL is a typical example of a URI that references a resource such as a Web site. For more information about URIs, see RFC 2396.

What might an attacker use the vulnerability to do? 
An attacker who has convinced a user to open an attachment in mail or to follow a link to an attacker"s Web site could run arbitrary code 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.

How could an attacker exploit the vulnerability? 
An attacker would have to create a specially crafted URI and provide the URI as input to an application on an affected system, which would then attempt to access the resource referred to it by the URI. Applications that take URIs as input from untrusted sources such as attachments in e-mail, documents, or data from the network assuming it will be safe, are exposed to this vulnerability. Under specific circumstances, processing specially crafted URI input could allow arbitrary code to be executed. In order to exploit the vulnerability, an attacker would have to convince the user to launch the attachment or application, or visit the Web site. 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 vulnerability might also be exploited by compromised Web sites or Web sites that accept or host user-provided content or advertisements. These Web sites could contain specially crafted URIs that could exploit this vulnerability. It could also be possible to display specially crafted URIs 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? 
Systems running supported editions of Windows XP and Windows Server 2003 with Internet Explorer 7 installed are vulnerable.

What does the update do? 
The update removes the vulnerability by changing the way that the Windows shell handles invalid URIs.

I do not have Windows Internet Explorer 7 installed. Why am I receiving this update? 
The vulnerability exists in a Windows file, Shell32.dll, included in supported editions of Windows XP and Windows Server 2003. Microsoft has not identified any way to exploit this vulnerability on systems using Internet Explorer 6, which is the browser that is included with these operating systems. As a defense-in-depth measure, this security update is made available to all customers using supported editions of Windows XP and Windows Server 2003, regardless of which version of Internet Explorer is installed.

I am using Windows Vista, am I at risk from this vulnerability? 
No. Windows Vista is not affected by this vulnerability. Windows Internet Explorer 7 is included with Windows Vista but the Windows shell in Windows Vista is not affected by this vulnerability.

When this security bulletin was issued, had this vulnerability been publicly disclosed? 
Yes. This vulnerability had been publicly disclosed when this security bulletin was originally issued. It has been assigned the Common Vulnerability and Exposure number CVE-2007-3896. This vulnerability was first described in Microsoft Security Advisory 943521.

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

Does applying this security update help protect customers from the code that has been published publicly that attempts to exploit this vulnerability? 
Yes. This security update addresses the vulnerability that is currently being exploited. The vulnerability that has been addressed has been assigned the Common Vulnerability and Exposure number CVE-2007-3896.

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startA("s"+sID)Detection and Deployment Tools and GuidanceendA()

Manage the software and security updates you need to deploy to the servers, desktop, and mobile computers in your organization. For more information see the TechNet Update Management Center. The Microsoft TechNet Security Web site provides additional information about security in Microsoft products.

Security updates are available from Microsoft Update, Windows Update, and Office Update. Security updates are also available from the Microsoft Download Center. You can find them most easily by doing a keyword search for "security update."

Finally, security updates can be downloaded from the Microsoft Update Catalog. The Microsoft Update Catalog provides a searchable catalog of content made available through Windows Update and Microsoft Update, including security updates, drivers and service packs. By searching using the security bulletin number (such as, “MS07-036”), you can add all of the applicable updates to your basket (including different languages for an update), and download to the folder of your choosing. For more information about the Microsoft Update Catalog, see the Microsoft Update Catalog FAQ.

Detection and Deployment Guidance

Microsoft has provided detection and deployment guidance for this month’s security updates. This guidance will also help IT professionals understand how they can use various tools to help deploy the security update, such as Windows Update, Microsoft Update, Office Update, the Microsoft Baseline Security Analyzer (MBSA), the Office Detection Tool, Microsoft Systems Management Server (SMS), and the Extended Security Update Inventory Tool. For more information, see Microsoft Knowledge Base Article 910723.

Microsoft Baseline Security Analyzer

Microsoft Baseline Security Analyzer (MBSA) allows administrators to scan local and remote systems for missing security updates as well as common security misconfigurations. For more information about MBSA, visit Microsoft Baseline Security Analyzer.

The following table provides the MBSA detection summary for this security update.

For more information about MBSA 2.0.1, see MBSA 2.0 Frequently Asked Questions.

Windows Server Update Services

By using Windows Server Update Services (WSUS), administrators can 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 to Windows 2000 and later operating systems. For more information about how to deploy this security update using Windows Server Update Services, visit the Windows Server Update Services Web site.

Systems Management Server

The following table provides the SMS detection and deployment summary for this security update.

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. See also Downloads for Systems Management Server 2.0.

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, see SMS 2003 Inventory Tool for Microsoft Updates. SMS 2003 can also use the Microsoft Office Inventory Tool to detect required updates for Microsoft Office applications. For more information about the Office Inventory Tool and other scanning tools, see SMS 2003 Software Update Scanning Tools. See also Downloads for Systems Management Server 2003.

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.

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startA("s"+sID)Security Update InformationendA()

Affected Software

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

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startA("s"+sID)Windows XP (all editions)endA()

Reference Table

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

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startA("s"+sID)File InformationendA()

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.

For all supported 32-bit editions of Windows XP:

For all supported x64-based editions of Windows XP Professional:

Note For a complete list of supported editions, see the Support Lifecycle Index. For a complete list of service packs, see Lifecycle Supported Service Packs. For more information on the support lifecycle policy, see Microsoft Support Lifecycle.

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startA("s"+sID)Deployment InformationendA()

Installing the Update

When you install this security update, 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.

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

This security update supports the following setup switches.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.

Removing the Update

This security update supports the following setup switches.

Verifying That the Update Has Been Applied

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startA("s"+sID)Windows Server 2003 (all editions)endA()

Reference Table

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

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startA("s"+sID)File InformationendA()

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.

For all supported 32-bit editions of Windows Server 2003:

For all supported Itanium-based editions of Windows Server 2003:

For all supported x64-based editions of Windows Server 2003:

Note For a complete list of supported editions, see the Support Lifecycle Index. For a complete list of service packs, see Lifecycle Supported Service Packs. For more information on the support lifecycle policy, see Microsoft Support Lifecycle.

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startA("s"+sID)Deployment InformationendA()

Installing the Update

When you install this security update, 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.

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

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.

Removing the Update

This security update supports the following setup switches.

Verifying that the Update Has Been Applied

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

Support

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