Security Bulletin

Microsoft Security Bulletin MS10-075 - Critical

Vulnerability in Media Player Network Sharing Service Could Allow Remote Code Execution (2281679)

Published: October 12, 2010

Version: 1.0

General Information

Executive Summary

This security update resolves a privately reported vulnerability in the Microsoft Windows Media Player Network Sharing Service. The vulnerability could allow remote code execution if an attacker sent a specially crafted RTSP packet to an affected system. However, Internet access to home media is disabled by default. In this default configuration, the vulnerability can be exploited only by an attacker within the same subnet.

This security update is rated Critical for supported editions of Windows 7 and Important for all supported editions of Windows Vista. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by correcting the way that Windows Media Player Network Sharing Service handles specially crafted RTSP packets. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. The majority of customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Known Issues. None

Affected and Non-Affected Software

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

Frequently Asked Questions (FAQ) Related to This Security Update

Where are the file information details?
Refer to the reference tables in the Security Update Deployment section for the location of the file information details.

I am running an affected version of Microsoft Windows but the Windows Media Player Network Sharing Service is not started. Will I be offered this update?
Yes, the update will be offered to all systems running an affected Windows operating system regardless of whether or not the Windows Media Player Network Sharing Service is started.

Why is Windows Vista rated as Important and Windows 7 rated as Critical?
On Windows 7 Home Basic and Windows 7 Home Premium editions, the Media Player Network Sharing Service is enabled by default; therefore, the vulnerability is rated Critical. For Windows 7 Professional, Windows 7 Enterprise, and Windows 7 Ultimate editions, the service is not enabled by default.

For affected versions of Windows Vista, by default, the service is not enabled. This mitigating factor lowers the severity rating on supported editions of Windows Vista to Important.

How is the Windows 7 Service Pack 1 Beta release affected by this vulnerability?
Windows 7 Service Pack 1 Beta is affected by the vulnerability described in this bulletin. Customers running these beta releases are encouraged to download and apply the update to their systems. Security updates are available from Microsoft Update and Windows Update. The security update is also available for download from the Microsoft Download Center.

I am using an older release 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 releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, visit the Microsoft Support Lifecycle Web site.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. To determine the support lifecycle for your software release, see Select a Product for Lifecycle Information. For more information about service packs for these software releases, see Lifecycle Supported Service Packs.

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 in the Contact Information list, 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 Microsoft Support Lifecycle Policy FAQ.

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the October bulletin summary. For more information, see Microsoft Exploitability Index.

RTSP Use After Free Vulnerability - CVE-2010-3225

A vulnerability exists in Microsoft Windows Media Player Network Sharing Service that could allow a remote user to send a specially crafted network packet to an instance of the application's network streaming service and cause remote code execution in the context of the current application.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-3225.

Mitigating Factors for RTSP Use After Free Vulnerability - CVE-2010-3225

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:

• By default, Internet access to home media is disabled. In this default configuration, the vulnerability can be exploited only by computers within the same subnet.
• On supported editions of Windows Vista and on Windows 7 Professional, Windows 7 Enterprise, and Windows 7 Ultimate editions, the Windows Media Player Network Sharing Service is not enabled by default.

Workarounds for RTSP Use After Free Vulnerability - CVE-2010-3225

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

• Disable Windows Media Player Network Sharing Service on affected systems

  Interactive Method

  Note Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or view the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe.

  1. Click Start, click Run, type Regedit in the Open box, and then click OK.
  2. Locate and then select the following registry key:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WMPNetworkSvc
  3. Click the File menu and then click Export.
  4. In the Export Registry File dialog box, enter WMPNetworkSvc_Backup.reg and then click Save.
     Note This will create a backup of this registry key in the My Documents folder by default.
  5. Select the value Start on the right pane in the Registry Editor. Press Enter to edit the value of the key. Change the Value data field to 4, and press Enter.
  6. From an elevated command prompt, stop the service by entering the following command:
     sc stop WMPNetworkSvc

  Managed Deployment Script

  1. Make a backup copy of the registry key using the following command:
     regedit /e WMPNetworkSvc_Backup.reg HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\WMPNetworkSvc
  2. Save the following to a file with a .REG extension (e.g., Disable_WMPNetworkSvc.reg):
     Windows Registry Editor Version 5.00
     HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\service_name]
     Start"=dword:00000004
  3. Run the registry script created in step 2 on the target machine with the following command:
     Regedit /s Disable_WMPNetworkSvc.reg
  4. From an elevated command prompt, stop the service by entering the following command:
     sc stop WMPNetworkSvc

  Impact of workaround. Windows Media Sharing will be disabled.

  How to undo the workaround.

  Using the interactive method:

  1. Click Start, click Run, type Regedit in the Open box, and then click OK.
  2. Click the File menu and then click Import.
  3. In the Import Registry File dialog box, select the WMPNetworkSvc_Backup.regfile that was created in the "Interactive Method" above, and then click Open.
  4. Exit Registry Editor, and then restart the computer.

  Using the managed deployment script:

  1. Run the registry script created in step 2 on the target machine with the following command:
     Regedit /s WMPNetworkSvc_Backup.reg
  2. Restart the computer.

FAQ for RTSP use after free vulnerability - CVE-2010-3225

What is the scope of the vulnerability? 
This is a remote code execution vulnerability. An attacker who successfully exploited this vulnerability could execute code in the security context of the Network Service account.

What causes the vulnerability? 
The vulnerability is caused by the way that the Microsoft Windows Media Player Network Sharing Service processes Real Time Streaming Protocol (RTSP) packets.

How could an attacker exploit the vulnerability? 
An attacker could exploit the vulnerability by creating and sending a specially crafted RTSP packet to an affected system.

What is RTSP? 
The Real Time Streaming Protocol (RTSP) is an application-level protocol for control over the delivery of data with real-time properties. RTSP provides an extensible framework to enable controlled, on-demand delivery of real-time data, such as audio and video. Sources of data can include both live data feeds and stored clips. This protocol is intended to control multiple data delivery sessions, provide a means for choosing delivery channels such as UDP, multicast UDP and TCP, and provide a means for choosing delivery mechanisms based upon RTP (RFC 1889). RTSP is defined in RFC 2326.

RTSP supports player control actions such as stopping, pausing, rewinding, and fast-forwarding indexed Windows Media files. You can use RTSP to stream content to computers running Windows Media Player 9 Series or later or Windows Media Services 9 Series or later.

What is the Network Service account? 
The Network Service account is a built-in account that has more access to resources and objects than members of the Users group. Services that run as the Network Service account access network resources by using the credentials of the computer account. The actual name of the account is NT AUTHORITY\NETWORK SERVICE. For more information, see the MSDN article, NetworkService Account.

What is Windows Media Player Network Sharing Service? 
Windows Media Player lets you share files in your library with other users on your home network and to browse the files that are in libraries that other users on your network are sharing. Windows Media Sharing uses the Windows Media Player Network Sharing Service.

How can I determine if the Windows Media Player Network Sharing Service is running on my system? 
Click Start, click Run, type Services.msc and then click OK. In the Services control panel, see whether the Windows Media Player Network Sharing Service has a status of "Started".

What might an attacker use the vulnerability to do? 
An attacker who successfully exploited this vulnerability could take control of an affected system in the security context of the Network Service account.

What systems are primarily at risk from the vulnerability? 
Systems running Windows Media Player Network Sharing Service (wmpnetwk.exe) to stream media are primarily at risk.

What does the update do? 
The update addresses the vulnerability by correcting the way that Windows Media Player Network Sharing Service handles specially crafted RTSP packets.

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

Update Information

Detection and Deployment Tools and Guidance

Manage the software and security updates you need to deploy to the servers, desktop, and mobile systems 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 and Windows 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 provides detection and deployment guidance for security updates. This guidance contains recommendations and information that can help IT professionals understand how to use various tools for detection and deployment of security updates. For more information, see Microsoft Knowledge Base Article 961747.

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.

Note For customers using legacy software not supported by the latest release of MBSA, Microsoft Update, and Windows Server Update Services, please visit Microsoft Baseline Security Analyzer and reference the Legacy Product Support section on how to create comprehensive security update detection with legacy tools.

Windows Server Update Services

Windows Server Update Services (WSUS) enables information technology administrators to deploy the latest Microsoft product updates to computers that are running the Windows operating system. For more information about how to deploy security updates using Windows Server Update Services, see the TechNet article, Windows Server Update Services.

Systems Management Server

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

For SMS 2.0 and SMS 2003, 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. For more information about SMS scanning tools, see SMS 2003 Software Update Scanning Tools. See also Downloads for Systems Management Server 2003.

System Center Configuration Manager 2007 uses WSUS 3.0 for detection of updates. For more information about Configuration Manager 2007 Software Update Management, visit System Center Configuration Manager 2007.

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.

Update Compatibility Evaluator and Application Compatibility Toolkit

Updates often write to the same files and registry settings required for your applications to run. This can trigger incompatibilities and increase the time it takes to deploy security updates. You can streamline testing and validating Windows updates against installed applications with the Update Compatibility Evaluator components included with Application Compatibility Toolkit.

The Application Compatibility Toolkit (ACT) contains the necessary tools and documentation to evaluate and mitigate application compatibility issues before deploying Microsoft Windows Vista, a Windows Update, a Microsoft Security Update, or a new version of Windows Internet Explorer in your environment.

Security Update Deployment

Affected Software

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

Windows Vista (all editions)

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.

Deployment Information

Installing the Update

When you install this security update, the installer checks whether 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 For more information about the wusa.exe installer, see Microsoft Knowledge Base Article 934307.

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 section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.

• File Version Verification

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

  1. Click Start and then enter an update file name in the Start Search box.
  2. When the file appears under Programs, right-click the file name and click Properties.
  3. On the General tab, compare the file size with the file information tables provided in the bulletin KB article.
  4. You can also click the Details tab and compare information, such as file version and date modified, with the file information tables provided in the bulletin KB article.
  5. Finally, you can also click 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.

Windows 7 (all editions)

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.

Deployment Information

Installing the Update

When you install this security update, the installer checks whether 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 For more information about the wusa.exe installer, see "Windows Update Stand-alone Installer" in the TechNet article, Miscellaneous Changes in Windows 7.

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 section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.

• File Version Verification

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

  1. Click Start and then enter an update file name in the Search box.
  2. When the file appears under Programs, right-click the file name and click Properties.
  3. On the General tab, compare the file size with the file information tables provided in the bulletin KB article.
  4. You can also click the Details tab and compare information, such as file version and date modified, with the file information tables provided in the bulletin KB article.
  5. Finally, you can also click 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.

Other Information

Acknowledgments

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

• Oleksandr Mirosh, working with TippingPoint's Zero Day Initiative, for reporting the RTSP use after free vulnerability (CVE-2010-3225)

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please visit the active protections Web sites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Support

• Customers in the U.S. and Canada can receive technical support from Security Support or 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates. For more information about available support options, see Microsoft Help and Support.
• 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.

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 (October 12, 2010): Bulletin published.

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