A user account was changed
User account attributes (`UserAccountControl`, SPN, logon hours, profile paths) were modified.
Event ID 4738 is emitted when any attribute of a user account is updated. Crucially, it captures exact changes in the `UserAccountControl` field (such as `DONT_EXPIRE_PASSWORD`, `SMARTCARD_REQUIRED`, `PASSWD_NOTREQD`, or `SMARTCARD_REQUIRED` removal), as well as additions of `Service Principal Names (SPNs)` (`ServicePrincipalNames`) onto user accounts, which enables **Kerberoasting**.
Failure Reason / Root Cause:
Helpdesk profile updates, or attacker setting `DONT_EXPIRE_PASSWORD` / adding SPNs to backdoor accounts.
Raw Event XML snippet
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-A5BA-3E3B0328C30D}" />
<EventID>4738</EventID>
<Version>0</Version>
<Level>0</Level>
<Task>12544</Task>
<Opcode>0</Opcode>
<Keywords>0x8020000000000000</Keywords>
<TimeCreated SystemTime="2026-07-17T09:54:44.900Z" />
<EventRecordID>1048576</EventRecordID>
<Correlation />
<Execution ProcessID="612" ThreadID="1024" />
<Channel>Security</Channel>
<Computer>DC01.enterprise.internal</Computer>
<Security />
</System>
<EventData>
<Data Name="SubjectUserSid">S-1-5-18</Data>
<Data Name="SubjectUserName">SYSTEM</Data>
<Data Name="SubjectDomainName">NT AUTHORITY</Data>
<Data Name="SubjectLogonId">0x3e7</Data>
<!-- Event telemetry fields specific to A user account was changed -->
</EventData>
</Event>MITRE ATT&CK mapping
| ID | Technique | Tactic |
|---|---|---|
T1098 | Account Manipulation | Persistence |
T1558.003 | Steal or Forge Kerberos Tickets: Kerberoasting | Credential Access |
Recommended actions
- Alert immediately on any 4738 event where `UserAccountControl` shows `Password Not Required` (`PASSWD_NOTREQD`) enabled.
- Monitor for SPN additions (`ServicePrincipalNames` changed from `-` to valid SPN) on non-service user accounts (`Kerberoasting backdoor setup`).
- Check for modifications to `AllowedToDelegateTo` indicating Kerberos delegation tampering.