PKU2U authentication using online identities must be prevented.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-21953	WN08-SO-000063	SV-48424r2_rule	ECSC-1	Medium

Description
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.

STIG	Date
Windows 8/8.1 Security Technical Implementation Guide	2017-05-17

Details

Check Text ( C-45093r2_chk )
Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.) Expand the Security Configuration and Analysis tree view. Navigate to Local Policies -> Security Options. If the value for "Network Security: Allow PKU2U authentication requests to this computer to use online identities" is not set to "Disabled", this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Subkey: \System\CurrentControlSet\Control\LSA\pku2u\ Value Name: AllowOnlineID Type: REG_DWORD Value: 0

Check Text ( C-45093r2_chk )

Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.)
Expand the Security Configuration and Analysis tree view.
Navigate to Local Policies -> Security Options.

If the value for "Network Security: Allow PKU2U authentication requests to this computer to use online identities" is not set to "Disabled", this is a finding.

The policy referenced configures the following registry value:

Registry Hive: HKEY_LOCAL_MACHINE
Subkey: \System\CurrentControlSet\Control\LSA\pku2u\

Value Name: AllowOnlineID

Type: REG_DWORD
Value: 0

Fix Text (F-41555r1_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".