MC674685 – Reminder: Security hardening changes for Netlogon and Kerberos effective October 10, 2023 Icon

check before: 2023-09-25


Office 365 general


World tenant, Online, Windows Desktop


Change type:

Admin impact



Windows updates released November 8, 2022 and later include changes that address security vulnerabilities affecting Windows Server domain controllers (DC). Among the addressed vulnerabilities is a Kerberos security bypass and elevation of privilege scenario involving alteration of Privilege Attribute Certificate (PAC) signatures. Changes to address this issue have been released following a series of phases throughout 2023, and are reaching the final stage of enforcement in October.

All domain-joined, machine accounts are affected by these vulnerabilities. For details on configuring these security requirements in your environment see KB5020805: How to manage Kerberos protocol changes related to CVE-2022-37967.

When will this happen:
As previously announced, Windows updates released on and after this October 10, 2023 will have the following effect:

Remove the ability to disable PAC signature addition (previously done via the registry subkey KrbtgtFullPacSignature)
Remove support for Audit mode (this enabled authentication whether PAC signatures were missing or invalid, and created audit logs for review).
Deny authentication to incoming service tickets without the new PAC signatures.

Change Category:


Release Phase:



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