MT.1166 - Local Admin Merge should be disabled.
Overview
Checks that local admin merge is disabled to block local exclusions in the assigned Microsoft Defender Antivirus policies.
Local admin policy override allows privilege escalation to bypass security controls, enabling local administrators to add exclusions that weaken endpoint protection.
Remediation action:
- Open Microsoft Endpoint Manager > Endpoint Security > Antivirus
- Edit the relevant Microsoft Defender Antivirus policy
- Enable Disable Local Admin Merge to prevent local overrides
If your antivirus settings are split across several policies, this setting only needs to be set in one of them, as long as that policy is assigned to every device that needs it. No other assigned policy should set a different value: Intune does not merge this setting, so a device that receives both values may end up with either one, or none.
Related links
- Policy merge and conflicts for Antivirus policy settings
- Configure Microsoft Defender Antivirus
- Microsoft Endpoint Manager
Test Metadata
| Field | Value |
|---|---|
| Test ID | MT.1166 |
| Severity | Medium |
| Suite | Maester |
| Product | Defender |
| Related products | Intune |
| Feature | Endpoint antivirus |
| Area | Devices and endpoints |
| Resource type | Policy |
| User impact | Low |
| Implementation cost | Medium |
| MITRE ATT&CK | T1685 Disable or Modify Tools, T1564.012 File/Path Exclusions |
| Supports controls | nist-800-53-r5:CM-6 |
| PowerShell test | Test-MtMdeDisableLocalAdminMerge |
| Services | Graph |
Source
- Test:
tests/maester/defender/Test.MT.1166.ps1 - Documentation:
tests/maester/defender/Test.MT.1166.md