Posture check · Account security
Invisible character in an account's name (T1036, T1098)
The account name, user principal name or a service principal name contains an invisible character, such as a zero-width space. Real names don't contain these.
Why it matters
Attackers add an invisible character so a name looks like another account's and still passes the directory's uniqueness check. It sets up KerberLoss and ResetNightmare impersonation.
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
servicePrincipalName,sAMAccountNameanduserPrincipalName
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
Check whether the name disguises another account. Then remove the invisible character: rename the account, correct the user principal name, or remove the service principal name.
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.
- Remove service principal name For user accounts and service accounts.Semi-Auto: you authorize each change. Full-Auto never runs it.
Kerberos stops issuing tickets for that name. Only the name with the invisible character is removed.
- 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 holds the disguised name while you confirm which account is legitimate. The name stays as it is for the investigation.
To repair it: Rename the account, or correct its user principal name, to remove the invisible character.
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.