MS16-072: Security update for Group Policy: June 14, 2016

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Summary

This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow elevation of privilege if an attacker launches a man-in-the-middle (MiTM) attack against the traffic passing between a domain controller and the target machine.

To learn more about the vulnerability, see Microsoft Security Bulletin MS16-072.

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Additional information about this security update

The following articles contain additional information about this security update as it relates to individual product versions. The articles may contain known issue information.

3159398 MS16-072: Description of the security update for Group Policy: June 14, 2016
3163017 Cumulative update for Windows 10: June 14, 2016
3163018 Cumulative update for Windows 10 Version 1511 and Windows Server 2016 Technical Preview 4: June 14, 2016

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Known issues

MS16-072 changes the security context with which user group policies are retrieved. This by-design behavior change protects customers’ computers from a security vulnerability. Before MS16-072 is installed, user group policies were retrieved by using the user’s security context. After MS16-072 is installed, user group policies are retrieved by using the computer's security context. This issue is applicable for the following KB articles:

3159398 MS16-072: Description of the security update for Group Policy: June 14, 2016
3163017 Cumulative update for Windows 10: June 14, 2016
3163018 Cumulative update for Windows 10 Version 1511 and Windows Server 2016 Technical Preview 4: June 14, 2016
3163016 Cumulative Update for Windows Server 2016 Technical Preview 5: June 14 2016

Symptoms

All user Group Policy, including those that have been security filtered on user accounts or security groups, or both, may fail to apply on domain joined computers.

Cause

This issue may occur if the Group Policy Object is missing the Read permissions for the Authenticated Users group or if you are using security filtering and are missing Read permissions for the domain computers group.

Resolution

To resolve this issue, use the Group Policy Management Console (GPMC.MSC) and follow one of the following steps:

Add the Authenticated Users group with Read Permissions on the Group Policy Object (GPO).
If you are using security filtering, add the Domain Computers group with read permission.

Note: If Loopback Processing is enabled in Merge mode you have to add the specific user(s) and the specific computer(s) for which the Group Policy is addressed. To do this, in the Group Policy Management Console, select the desired Group Policy, and then click the Scope tab. In the Security Filtering area, click Add, and then add the specific users and computers.

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How to obtain and install the update

Method 1: Windows Update

This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to turn on automatic updating, see Get security updates automatically.

Note For Windows RT 8.1, this update is available through Windows Update only.

Method 2: Microsoft Download Center

You can obtain the stand-alone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.

Click the download link in Microsoft Security Bulletin MS16-072 that corresponds to the version of Windows that you are running.

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