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Microsoft Security Bulletin MS09-036 - Important

Vulnerability in ASP.NET in Microsoft Windows Could Allow Denial of Service (970957)

Published: | Updated:

Version: 1.1

General Information

Executive Summary

This security update addresses a privately reported Denial of Service vulnerability in the Microsoft .NET Framework component of Microsoft Windows. This vulnerability can be exploited only when Internet Information Services (IIS) 7.0 is installed and ASP.NET is configured to use integrated mode on affected versions of Microsoft Windows. An attacker could create specially crafted anonymous HTTP requests that could cause the affected Web server to become non-responsive until the associated application pool is restarted. Customers who are running IIS 7.0 application pools in classic mode are not affected by this vulnerability.

This security update is rated Important for all affected versions of Microsoft Windows. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by changing the way ASP.NET manages request scheduling. 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 at the earliest opportunity 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 SystemComponentMaximum Security ImpactAggregate Severity RatingBulletins Replaced by this Update
Windows Vista*Microsoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972591) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972592)Denial of ServiceImportantNone
Windows Vista Service Pack 1*Microsoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972593) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972594)Denial of ServiceImportantNone
Windows Vista x64 Edition*Microsoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972591) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972592)Denial of ServiceImportantNone
Windows Vista x64 Edition Service Pack 1*Microsoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972593) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972594)Denial of ServiceImportantNone
Windows Server 2008 for 32-bit Systems**Microsoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972593) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972594)Denial of ServiceImportantNone
Windows Server 2008 for x64-based Systems**Microsoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972593) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972594)Denial of ServiceImportantNone
Windows Server 2008 for Itanium-based SystemsMicrosoft .NET Framework 2.0 Service Pack 1 and Microsoft .NET Framework 3.5 (KB972593) and Microsoft .NET Framework 2.0 Service Pack 2 and Microsoft .NET Framework 3.5 Service Pack 1 (KB972594)Denial of ServiceImportantNone

* Because IIS 7.0 does not run on Windows Vista Starter and Windows Vista Home Basic, the following editions are not affected: Windows Vista Starter (32-bit), Windows Vista Home Basic (32-bit), and Windows Vista Home Basic (64-bit).

**Windows Server 2008 server core installation not affected. The vulnerability addressed by this update does not affect supported editions of Windows Server 2008 if Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; see Compare Server Core Installation Options.

Non-Affected Software

Operating System
Microsoft Windows 2000 Service Pack 4
Windows XP Service Pack 2
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 Service Pack 2
Windows Vista x64 Edition Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2
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

Frequently Asked Questions (FAQ) Related to This Security Update

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

Remote Unauthenticated Denial of Service in ASP.NET Vulnerability - CVE-2009-1536

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:

  • Alexander Pfandt of Digitaria for reporting the Remote Unauthenticated Denial of Service in ASP.NET Vulnerability (CVE-2009-1536)

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 (August 11, 2009): Bulletin published.
  • V1.1 (August 13, 2009): Clarified in Frequently Asked Questions (FAQ) Related to This Security Update that this security update will only be offered when IIS 7.0 is installed. Added information to the FAQ for Remote Unauthenticated Denial of Service in ASP.NET Vulnerability – CVE-2009-1536 about the difference between Integrated Mode and Classic Mode in IIS 7.0. This is an informational change only. Customers who have successfully installed this update do not need to reinstall.