Posture check · Account security
User principal name disguised as another account's name (T1098)
With invisible characters removed, the part of this user principal name before the @ matches another account's sAMAccountName (pre-Windows 2000 name) in the same forest.
Why it matters
A user principal name disguised as an administrator's name can take over Kerberos name lookups and reset that administrator's password (ResetNightmare).
How GraphnAI finds it
It runs after every sync, across all your connected domains at once. It applies to Active Directory.
It reads:
- The directory attributes
userPrincipalNameandsAMAccountName - The forest each domain belongs to
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.
How Select Fire™ contains it
How to fix it
Correct the user principal name so it no longer matches another account's sAMAccountName.
What Select Fire does
Select Fire opens from the finding and simulates each change on your live graph before anything changes in your directory. These steps contain a suspected compromise.
- Disable user For user accounts and service accounts.Semi-Auto, or Full-Auto when an Admin allows this action and every Full-Auto check passes. Never on a Tier 0 or Tier 1 account.
Disabling the account stops the impersonating name being used to authenticate. The name itself stays in place for the investigation.
To repair it: Change the user principal name so it no longer matches another account's sAMAccountName.
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.