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Microsoft Security Bulletin MS12-069 - Important

Vulnerability in Kerberos Could Allow Denial of Service (2743555)

Published: | Updated:

Version: 1.1

General Information

Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Windows. The vulnerability could allow denial of service if a remote attacker sends a specially crafted session request to the Kerberos server. 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 Important for all supported editions of Windows 7 and Windows Server 2008 R2. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by correcting how the Microsoft Kerberos implementation handles a specially crafted session. 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. Most 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, see Microsoft Support Lifecycle.

Affected Software 

Operating SystemMaximum Security ImpactAggregate Severity RatingUpdates Replaced
Windows 7
Windows 7 for 32-bit Systems
(KB2743555)
Denial of ServiceImportantKB2425227 in MS11-013 replaced by KB2743555
Windows 7 for 32-bit Systems Service Pack 1
(KB2743555)
Denial of ServiceImportantKB2425227 in MS11-013 replaced by KB2743555
Windows 7 for x64-based Systems
(KB2743555)
Denial of ServiceImportantKB2425227 in MS11-013 replaced by KB2743555
Windows 7 for x64-based Systems Service Pack 1
(KB2743555)
Denial of ServiceImportantKB2425227 in MS11-013 replaced by KB2743555
Windows Server 2008 R2
Windows Server 2008 R2 for x64-based Systems
(KB2743555)
Denial of ServiceImportantNone
Windows Server 2008 R2 for x64-based Systems Service Pack 1
(KB2743555)
Denial of ServiceImportantNone
Windows Server 2008 R2 for Itanium-based Systems
(KB2743555)
Denial of ServiceImportantKB2425227 in MS11-013 replaced by KB2743555
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1
(KB2743555)
Denial of ServiceImportantKB2425227 in MS11-013 replaced by KB2743555
Server Core installation option
Windows Server 2008 R2 for x64-based Systems (Server Core installation)
(KB2743555)
Denial of ServiceImportantNone
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
(KB2743555)
Denial of ServiceImportantNone

 

Non-Affected Software

Operating System
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 8 for 32-bit Systems
Windows 8 for 64-bit Systems
Windows Server 2012
Server Core installation option
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
Windows Server 2012 (Server Core installation)

Frequently Asked Questions (FAQ) Related to This Security Update

Vulnerability Information

Severity Ratings and Vulnerability Identifiers

Kerberos NULL Dereference Vulnerability - CVE-2012-2551

Update Information

Detection and Deployment Tools and Guidance

Security Update Deployment

Other Information

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 go to the active protections websites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Support

How to obtain help and support for this security update

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 9, 2012): Bulletin published.
  • V1.1 (May 29, 2013): Corrected update replacement entries in the Affected Software table for x64-based editions of Windows Server 2008 R2. This is a bulletin change only. There were no changes to detection logic or security update files.