Microsoft Security Bulletin MS10-025 - Critical Vulnerability in Microsoft Windows Media Services Could Allow Remote Code Execution (980858)

Microsoft Security Bulletin MS10-025 - Critical
Vulnerability in Microsoft Windows Media Services Could Allow Remote Code Execution (980858)
Published: April 13, 2010 | Updated: April 14, 2010

Version: 1.1
General Information
Executive Summary

This security update resolves a privately reported vulnerability in Windows Media Services running on Microsoft Windows 2000 Server. The vulnerability could allow remote code execution if an attacker sent a specially crafted transport information packet to a Microsoft Windows 2000 Server system running Windows Media Services. Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate from outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed. On Microsoft Windows 2000 Server, Windows Media Services is an optional component and is not installed by default.

This security update is rated Critical for all supported editions of Microsoft Windows 2000 Server. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by modifying the way that the Windows Media Unicast Service (nsum.exe) handles transport info network 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 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
Top of sectionTop of section
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
Operating System Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update

Microsoft Windows 2000 Server Service Pack 4

Remote Code Execution

Critical

None

Non-Affected Software
Operating System

Microsoft Windows 2000 Professional Service Pack 4

Windows XP Service Pack 2 and Windows XP Service Pack 3

Windows XP Professional x64 Edition Service Pack 2

Windows Server 2003 Service Pack 2

Windows Server 2003 x64 Edition Service Pack 2

Windows Server 2003 with SP2 for Itanium-based Systems

Windows Vista, Windows Vista Service Pack 1, and Windows Vista Service Pack 2

Windows Vista x64 Edition, Windows Vista x64 Edition Service Pack 1, and Windows Vista x64 Edition Service Pack 2

Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2

Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2

Windows Server 2008 for Itanium-based Systems and Windows Server 2008 for Itanium-based Systems Service Pack 2

Windows 7 for 32-bit Systems

Windows 7 for x64-based Systems

Windows Server 2008 R2 for x64-based Systems

Windows Server 2008 R2 for Itanium-based Systems
Top of sectionTop of section

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.

My system is not running Windows Media Services. Will I be offered this update?
No, Microsoft Windows 2000 systems not running the optional Windows Media Services will not be offered this security update. If Windows Media Services is running, the security update will be offered.

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.
Top of sectionTop of section
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 April bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Media Services Stack-based Buffer Overflow Vulnerability - CVE-2010-0478 Aggregate Severity Rating

Microsoft Windows 2000 Server Service Pack 4

Critical
Remote Code Execution

Critical
Top of sectionTop of section

Media Services Stack-based Buffer Overflow Vulnerability - CVE-2010-0478

A remote code execution vulnerability exists in Microsoft Windows 2000 Server Service Pack 4 running the optional Windows Media Services component due to the way the Windows Media Unicast Service handles specially crafted transport information packets. On Microsoft Windows 2000 Server Service Pack 4, Windows Media Services is an optional component and is not installed by default. Only Microsoft Windows 2000 Server systems that have enabled Windows Media Services are affected by this vulnerability.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-0478.

Mitigating Factors for Media Services Stack-based Buffer Overflow Vulnerability - CVE-2010-0478

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:
•

Supported editions of Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2 are not affected by the vulnerability described in this bulletin.
•

By default, Windows Media Services is not enabled on Microsoft Windows 2000 Server. In order for a Microsoft Windows 2000 Server to be vulnerable, the server would have to be configured as a streaming media server by adding the Windows Media Services component in the Windows Components Wizard.
Top of sectionTop of section

Workarounds for Media Services Stack-based Buffer Overflow Vulnerability - CVE-2010-0478

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:
•

Stop and disable Windows Media Unicast Service

As an Administrator, disable the Windows Media Unicast Service by using the following command at the command prompt:

sc stop nsunicast & sc config nsunicast start= disabled

Impact of workaround. Connections to the streaming media server via the Windows Media Unicast Service will not be allowed.

How to undo the workaround.

As an Administrator, enable the Windows Media Unicast Service by using the following command at the command prompt:

sc config nsunicast start= auto & sc start nsunicast
•

Uninstall the Windows Media Services component using Windows Component Wizard

Log on to the computer as an administrator or a member of the Administrators group.

Click Start, point to Settings, and then click Control Panel.

In Control Panel, double-click Add/Remove Programs.

Click Add/Remove Windows Components. The Windows Components Wizard starts and the Windows Components screen is displayed.

Clear the Windows Media Services check box. Click Next and follow the instructions in the Windows Component Wizard.

Impact of workaround. The server will no longer be configured as a streaming media server using Windows Media Services.

How to undo the workaround. Install Windows Media Services via Windows Components Wizard.
Top of sectionTop of section

FAQ for Media Services Stack-based Buffer Overflow Vulnerability - CVE-2010-0478

What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.

What causes the vulnerability?
This vulnerability is caused by the way that Windows Media Services running on Microsoft Windows 2000 Server Service Pack 4 handles transport information network packets.

What is Windows Media Services?
Microsoft Windows Media Services is an industrial-strength platform for streaming live or on-demand audio and video content over the Internet or an intranet. Use Windows Media Services to configure and manage one or more Windows Media servers that deliver your content to clients.

Your clients can be:
•

Computers or devices that play the content using a player, such as Windows Media Player.
•

Computers running Windows Media Services that are proxying, caching, or redistributing your content.
•

Custom applications that have been developed using the Windows Media Software Development Kit (SDK).

What component of Windows Media Services is vulnerable?
The vulnerable code exists in the Windows Media Unicast Service (nsum.exe).

What is the Windows Media Unicast Service?
The Windows Media Unicast Service is one of the Windows Media Services, which is a family of services that enable digital content providers to send streaming media to customers. There are four services in the family:
•

Windows Media Unicast Service, which allows streaming media to be sent to a specific end user.
•

Windows Media Station Service, which allows a single stream of media to be sent to multiple end users at once.
•

Windows Media Program Service, which controls how many times a group of streams is played.
•

Windows Media Monitor Service, which enables the digital content provider to monitor end users connected to publishing points.

Only the Windows Media Unicast Service is affected by this vulnerability. This vulnerability cannot be used against the other three services.

What might an attacker use the vulnerability to do?
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.

How could an attacker exploit the vulnerability?
To exploit this vulnerability, an attacker could send a specially crafted transport information packet to a computer running Windows Media Services on Microsoft Windows 2000 Server Service Pack 4. Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate from outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.

On Microsoft Windows 2000 Server Service Pack 4, Windows Media Services is an optional component and is not installed by default.

What systems are primarily at risk from the vulnerability?
Microsoft Windows 2000 Server Service Pack 4 systems running Windows Media Services are affected by this vulnerability.

What does the update do?
This update addresses the vulnerability by modifying the way that the Windows Media Unicast Service handles transport information network packets.

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.

Other Information
Acknowledgments

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

Fabien Perigaud of CERT-LEXSI for reporting the Media Services Stack-based Buffer Overflow Vulnerability (CVE-2010-0478)
Top of sectionTop of section
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.
Top of sectionTop of section
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.
Top of sectionTop of section
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 (April 13, 2010): Bulletin published.
•

V1.1 (April 14, 2010): Corrected the restart requirement for Microsoft Windows 2000 Server.