Microsoft Defender AV must configure local administrator merge behavior for lists.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-278656WNDF-AV-000052SV-278656r1190744_ruleCCI-001170medium
Description
This policy setting configures how locally defined lists are combined or merged with globally defined lists. This setting applies to exclusion lists, specified remediation lists, and attack surface reduction.
STIGDate
Microsoft Defender Antivirus Security Technical Implementation Guide2026-02-17

Details

Check Text (C-278656r1190744_chk)

Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Configure local administrator merge behavior for lists is set to "Enabled". Otherwise, this is a finding. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender Criteria: If the value "DisableLocalAdminMerge" is REG_DWORD = 1, this is not a finding. If the value is 0, this is a finding.

Fix Text (F-83095r1190743_fix)

Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Configure local administrator merge behavior for lists to "Enabled".