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Microsoft Security Bulletin MS11-042 - Critical

Vulnerabilities in Distributed File System Could Allow Remote Code Execution (2535512)

Published: | Updated:

Version: 1.1

General Information

Executive Summary

This security update resolves two privately reported vulnerabilities in the Microsoft Distributed File System (DFS). The more severe of these vulnerabilities could allow remote code execution when an attacker sends a specially crafted DFS response to a client-initiated DFS request. An attacker who successfully exploited this vulnerability could execute arbitrary code and take complete control of an affected system. Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.

This security update is rated Critical for all supported editions of Windows XP and Windows Server 2003; Important for all supported editions of Windows Vista and Windows Server 2008; and Important for Windows 7 for 32-bit Systems, Windows 7 for x64-based Systems, Windows Server 2008 R2 for x64-based Systems, and Windows Server 2008 R2 for Itanium-based Systems. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerabilities by correcting the way that the DFS client validates fields in specially crafted DFS referral responses and by correcting the way that the DFS service handles specially crafted DFS referral responses. For more information about the vulnerabilities, 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

Operating SystemMaximum Security ImpactAggregate Severity RatingBulletins Replaced by this Update
Windows XP Service Pack 3Remote Code ExecutionCriticalNone
Windows XP Professional x64 Edition Service Pack 2Remote Code ExecutionCriticalNone
Windows Server 2003 Service Pack 2Remote Code ExecutionCriticalNone
Windows Server 2003 x64 Edition Service Pack 2Remote Code ExecutionCriticalNone
Windows Server 2003 with SP2 for Itanium-based SystemsRemote Code ExecutionCriticalNone
Windows Vista Service Pack 1 and Windows Vista Service Pack 2Denial of ServiceImportantNone
Windows Vista x64 Edition Service Pack 1 and Windows Vista x64 Edition Service Pack 2Denial of ServiceImportantNone
Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2*Denial of ServiceImportantNone
Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2*Denial of ServiceImportantNone
Windows Server 2008 for Itanium-based Systems and Windows Server 2008 for Itanium-based Systems Service Pack 2Denial of ServiceImportantNone
Windows 7 for 32-bit SystemsDenial of ServiceImportantNone
Windows 7 for x64-based SystemsDenial of ServiceImportantNone
Windows Server 2008 R2 for x64-based Systems*Denial of ServiceImportantNone
Windows Server 2008 R2 for Itanium-based SystemsDenial of ServiceImportantNone

*Server Core installation affected. This update applies, with the same severity rating, to supported editions of Windows Server 2008 or Windows Server 2008 R2 as indicated, whether or not installed using the Server Core installation option. For more information on this installation option, see the TechNet articles, Managing a Server Core Installation and Servicing a Server Core Installation. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008 and Windows Server 2008 R2; see Compare Server Core Installation Options.

Non-Affected Software

Operating System
Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1

Frequently Asked Questions (FAQ) Related to This Security Update

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

DFS Memory Corruption Vulnerability - CVE-2011-1868

DFS Referral Response Vulnerability - CVE-2011-1869

Update Information

Detection and Deployment Tools and Guidance

Security Update Deployment

Other Information

Acknowledgments

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

  • Laurent Gaffié of NGS Software for reporting the DFS Referral Response Vulnerability (CVE-2011-1869)

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 (June 14, 2011): Bulletin published.
  • V1.1 (June 14, 2011): Moved Windows 7 for 32-bit Systems Service Pack 1, Windows 7 for x64-based Systems Service Pack 1, Windows Server 2008 R2 for x64-based Systems Service Pack 1, and Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 from the affected software table to the non-affected software table. This is an informational change only. There were no changes to the security update files or detection logic.