Microsoft Security Bulletin MS15-127 - Critical

Security Update for Microsoft Windows DNS to Address Remote Code Execution (3100465)

Published: December 8, 2015

Version: 1.0

Executive Summary

This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow remote code execution if an attacker sends specially crafted requests to a DNS server.

This security update is rated Critical for all supported releases of Windows Server 2008 for 32-bit Systems, Windows Server 2008 for x64-based Systems, Windows Server 2008 R2 for x64-based Systems, Windows Server 2012, and Windows Server 2012 R2. For more information, see the Affected Software section.

The security update addresses the vulnerability by modifying how DNS servers parse requests. For more information about the vulnerability, see the Vulnerability Information section.

For more information about this update, see Microsoft Knowledge Base Article 3100465.

Affected Software and Vulnerability Severity Ratings

The following software versions or editions are affected. Versions or editions that are not listed 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.

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 December bulletin summary.

Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Windows DNS Use After Free Vulnerability – CVE-2015-6125 Updates Replaced*
Windows Server 2008
Windows Server 2008 for 32-bit Systems Service Pack 2
(3100465)
Critical
Remote Code Execution
2647170 in MS12-017
Windows Server 2008 for x64-based Systems Service Pack 2
(3100465)
Critical
Remote Code Execution
2647170 in MS12-017
Windows Server 2008 R2
Windows Server 2008 R2 for x64-based Systems Service Pack 1
(3100465)
Critical
Remote Code Execution
2647170 in MS12-017
Windows Server 2012 and Windows Server 2012 R2
Windows Server 2012
(3100465)
Critical
Remote Code Execution
None
Windows Server 2012 R2
(3100465)
Critical
Remote Code Execution
None
Server Core installation option
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
(3100465)
Critical
Remote Code Execution
2647170 in MS12-017
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
(3100465)
Critical
Remote Code Execution
2647170 in MS12-017
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
(3100465)
Critical
Remote Code Execution
2647170 in MS12-017
Windows Server 2012 (Server Core installation)
(3100465)
Critical
Remote Code Execution
None
Windows Server 2012 R2 (Server Core installation)
(3100465)
Critical
Remote Code Execution
None

[1]This update is only available via Windows Update.

Note Windows Server Technical Preview 3 and Windows Server Technical Preview 4 are affected. Customers running this operating system are encouraged to apply the update, which is available via Windows Update.

*The Updates Replaced column shows only the latest update in any chain of superseded updates. For a comprehensive list of updates replaced, go to the Microsoft Update Catalog, search for the update KB number, and then view update details (updates replaced information is provided on the Package Details tab).

Vulnerability Information

Windows DNS Use After Free Vulnerability – CVE-2015-6125

A remote code execution vulnerability exists in Windows Domain Name System (DNS) servers when they fail to properly parse requests. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the Local System Account. Windows servers that are configured as DNS servers are at risk from this vulnerability.

An attacker could create a specially crafted application to connect to a Windows DNS server and then issue malicious requests to the server. The update addresses the vulnerability by modifying how Windows DNS servers parse requests.

Microsoft received information about this vulnerability through coordinated vulnerability disclosure. At the time this security bulletin was originally issued, Microsoft was unaware of any attack attempting to exploit this vulnerability.

Mitigating Factors

Microsoft has not identified any mitigating factors for this vulnerability.

Workarounds

Microsoft has not identified any workarounds for this vulnerability.

Security Update Deployment

For Security Update Deployment information, see the Microsoft Knowledge Base article referenced here in the Executive Summary.

Acknowledgments

Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgments for more information.

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 (December 8, 2015): Bulletin published.

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