Posture check · Group Policy
Domain controllers accept LAN Manager or NTLMv1 authentication (T1557, T1550.002)
No Group Policy sets these domain controllers to refuse LAN Manager and NTLMv1, so they accept both.
Why it matters
Any system that still authenticates with these protocols exposes a response that can be cracked or relayed against the domain controllers.
How GraphnAI finds it
It runs after every sync, on each connected domain or tenant on its own. It applies to Active Directory.
It reads:
- The directory attributes
gPLink,gPOptions,flags,userAccountControl,accountEnabled,distinguishedName,gPCWQLFilterandnTSecurityDescriptor - The Group Policy files the Identity Bridge reads from SYSVOL
Tiered Fidelity™ level: Theoretical
Every finding from this check carries the Theoretical level.
- TheoreticalThis checkConfigured in the directory. Nothing else checked.
- ConstrainedA constraint on it has been checked.
- ValidatedTelemetry has seen it in use.
Why there's no automatic fix
GraphnAI can't edit Group Policy settings. Change this setting in Group Policy Management.
How to fix it
Set 'Network security: LAN Manager authentication level' to 'Send NTLMv2 response only. Refuse LM & NTLM' in a policy that applies to the domain controllers. First confirm no system still needs the older protocols.
Related checks
MITRE ATT&CK® technique names and MITRE D3FEND™ technique labels: © The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. ATT&CK® is a registered trademark and D3FEND™ a trademark of The MITRE Corporation.
See it on your own directory.
The Public Preview is free for 30 days from your first sync, on your own server.