Author Topic: Microsoft fixes Windows Kerberos auth issues in emergency updates  (Read 83 times)

Offline javajolt

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Microsoft has released optional out-of-band (OOB) updates to fix a known issue triggering Kerberos sign-in failures and other authentication problems on enterprise Windows domain controllers after installing cumulative updates released during November's Patch Tuesday.

The company acknowledged and started investigating on Monday when it also said that the known issue could affect any Kerberos authentication scenario within affected enterprise environments.

While Microsoft has also started enforcing security hardening for Kerberos and Netlogon beginning with the November 2022 Patch Tuesday, it said that these auth problems are not an expected result.

Auth issues on impacted Windows versions

"After installing updates released on November 8, 2022, or later on Windows Servers with the Domain Controller role, you might have issues with Kerberos authentication," Microsoft explained.

"When this issue is encountered you might receive a Microsoft-Windows-Kerberos-Key-Distribution-Center Event ID 14 error event in the System section of Event Log on your Domain Controller with the below text."

The list of impacted Kerberos auth scenarios includes but is not limited to the following:

   • ​Domain user sign-in might fail. This also might affect Active Directory
      Federation Services (AD FS)
authentication.

   • Group Managed Service Accounts (gMSA) used for services such as
      Internet Information Services (IIS Web Server) might fail to authenticate.

   • Remote Desktop connections using domain users might fail to connect.

   • You might be unable to access shared folders on workstations and file shares on servers.

   • Printing that requires domain user authentication might fail.

Fix released for affected Windows versions

Today, Microsoft has released OOB emergency updates that Windows admins have to install on all Domain Controllers (DCs) in affected environments.

"You do not need to install any update or make any changes to other servers or client devices in your environment to resolve this issue," Microsoft says.

"If you used any workaround or mitigations for this issue, they are no longer needed, and we recommend you remove them."

The OOB updates released today are available only via the Microsoft Update Catalog and will not be offered via Windows Update.

Redmond has released cumulative updates for installation on Domain Controllers (no action needed on the client side):

   • Windows Server 2022: KB5021656

   • Windows Server 2019: KB5021655

   • Windows Server 2016: KB5021654

Microsoft also released standalone updates which can be imported into Windows Server Update Services (WSUS) and Microsoft Endpoint Configuration Manager:

   • Windows Server 2012 R2: KB5021653

   • Windows Server 2012: KB5021652

   • Windows Server 2008 SP2: KB5021657

The only affected platform still waiting for a fix is Windows Server 2008 R2 SP1. Redmond says that a dedicated update will be made available next week.

You can find detailed WSUS deployment instructions on the WSUS and the Catalog Site and Configuration Manager instructions on the Import updates from the Microsoft Update Catalog page.

"If you are using security-only updates for these versions of Windows Server, you only need to install these standalone updates for the month of November 2022," Microsoft added.

"If you are using Monthly rollup updates, you will need to install both the standalone updates listed above to resolve this issue, and install the Monthly rollups released November 8, 2022, to receive the quality updates for November 2022."

Two years ago, Redmond addressed similar Kerberos auth problems affecting Windows systems caused by security updates released with the November 2020 Patch Tuesday.

source
« Last Edit: November 18, 2022, 01:37:36 PM by javajolt »