Microsoft Security Bulletin MS15-120 - Important

Security Update for IPSec to Address Denial of Service (3102939)

Published: November 10, 2015

Version: 1.0

Executive Summary

This security update resolves a denial of service vulnerability in Microsoft Windows. An attacker who successfully exploited the vulnerability could cause the system to become nonresponsive. To exploit the vulnerability an attacker must have valid credentials.

This security update is rated Important for all supported releases of Windows 8, Windows Server 2012, Windows RT, Windows 8.1, Windows Server 2012 R2, and Windows RT 8.1. For more information, see the Affected Software section.

The update addresses the vulnerability by adding an additional check to verify encryption negotiation. For more information about the vulnerability, see the Vulnerability Information section.

For more information about this update, see Microsoft Knowledge Base Article 3102939.

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 November bulletin summary.

Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Windows IPSec Denial of Service Vulnerability - CVE-2015-6111 Updates Replaced
Windows 8 and Windows 8.1
Windows 8 for 32-bit Systems (3102939) Important Denial of Service None
Windows 8 for x64-based Systems (3102939) Important Denial of Service None
Windows 8.1 for 32-bit Systems (3102939) Important Denial of Service None
Windows 8.1 for x64-based Systems (3102939) Important Denial of Service None
Windows Server 2012 and Windows Server 2012 R2
Windows Server 2012 (3102939) Important Denial of Service None
Windows Server 2012 R2 (3102939) Important Denial of Service None
Windows RT and Windows RT 8.1
Windows RT[1]\ (3102939) Important Denial of Service None
Windows RT 8.1[1]\ (3102939) Important Denial of Service None
Server Core installation option
Windows Server 2012 (Server Core installation) \ (3102939) Important Denial of Service None
Windows Server 2012 R2 (Server Core installation) \ (3102939) Important Denial of Service None

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

Vulnerability Information

Windows IPSec Denial of Service Vulnerability - CVE-2015-6111

A denial of service vulnerability exists in Windows when the Internet Protocol Security (IPSec) service improperly handles encryption negotiation. An attacker who successfully exploited the vulnerability could cause the system to become nonresponsive.

To exploit this vulnerability an attacker must have valid credentials. An attacker could exploit this vulnerability by using a malicious application to connect to a target machine and cause the server to become nonresponsive. The update addresses the vulnerability by adding an additional check to verify encryption negotiation.

This vulnerability has been publicly disclosed. It has been assigned Common Vulnerability and Exposure number CVE-2015-6111. 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 (November 10, 2015): Bulletin published.

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