MT.1166: Local Admin Merge should be disabled.
| ID | MT.1166 |
| Severity | Medium |
| Suite | Mito |
| Product | Defender |
| Related products | Intune |
| Feature | Endpoint antivirus |
| Security area | Devices and endpoints |
| Resource type | Policy |
| User impact of fixing | Low |
| Effort to fix | Medium |
| Framework controls | nist-800-53-r5:CM-6 Configuration Settings |
| MITRE ATT&CK | T1685, T1564.012 |
| Reads from | Microsoft Graph |
What this checks and how to fix it
Section titled “What this checks and how to fix it”Checks that local admin merge is disabled to block local exclusions in all 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:
Section titled “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
Related links
Section titled “Related links”Mito check. Author: bdrogja. Open-source licences.
Open-source licences. CIS Benchmark material © Center for Internet Security, Inc.; CISA SCuBA baselines are public domain (CC0).
© 2026 Virtual Petals. Mito is a Virtual Petals service, hosted in Microsoft Azure UAE North.