An elevation of privilege vulnerability exists in Microsoft Windows when a man-in-the-middle attacker is able to successfully forward an authentication request to a Windows LDAP server, such as a system running Active Directory Domain Services or Active Directory Lightweight Directory Services, which has been configured to require signing or sealing on incoming connections.
The update addresses this vulnerability by incorporating support for Extended Protection for Authentication security feature, which allows the LDAP server to detect and block such forwarded authentication requests once enabled.
To learn more about the vulnerability, see CVE-2017-8563.
- After installing the security updates for CVE-2017-8563, administrators need to set the registry subkey LdapEnforceChannelBinding to enable the fix for the CVE. For more information about setting the registry key, see Microsoft Knowledge Base article 4034879.
- If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.
Windows Server 2008 and older systems require that Microsoft Security Advisory 973811, available in “KB 968389 Extended Protection for Authentication”, be installed before installing CVE-2017-8563. If you install CVE-2017-8563 without KB 968389 on a Domain controller or AD LDS instance, all LDAPS connections will fail with LDAP error 81 - LDAP_SERVER_DOWN. In addition, we strongly recommended that you also review and install the fixes documented in the Known Issues section of KB 968389.
How to obtain and install the update
Method 1: Windows Update
Method 2: Microsoft Update Catalog
The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current-daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows Server 2008 file information
The MANIFEST files (.manifest) and MUM files (.mum) that are installed are not listed.