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WN25-SO-000280 Windows Server 2025 must prevent PKU2U authentication using online identities.

DISA STIG library V1R4
All changes in this version
first version loaded CAT II

Maps to CM-6 via CCI-000366

Title

Windows Server 2025 must prevent PKU2U authentication using online identities.

Control

If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Control\LSA\pku2u\ Value Name: AllowOnlineID Type: REG_DWORD Value: 0x00000000 (0)

Discussion

PKU2U is a peer-to-peer authentication protocol. This setting prevents online identities from authenticating to domain-joined systems. Authentication will be centrally managed with Windows user accounts.

Related controls

CCI-000366

Fix

Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> Network security: Allow PKU2U authentication requests to this computer to use online identities to "Disabled".