A directory service object was undeleted
An Active Directory object previously marked as deleted (`isDeleted=TRUE`) was restored from the AD Recycle Bin.
Event ID 5138 records object undelete operations across Active Directory (`Active Directory Recycle Bin restoration`). While legitimate during accidental deletion recovery, adversaries sometimes undelete previously compromised user accounts or computer accounts (`DCShadow` / zombie objects) to restore backdoor access without generating standard `Account Created` (`4720`) events.
Failure Reason / Root Cause:
Undelete API operation performed on AD object (`ObjectDN`).
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>5138</EventID>
<Version>0</Version>
<Level>0</Level>
<Task>12544</Task>
<Opcode>0</Opcode>
<Keywords>0x8020000000000000</Keywords>
<TimeCreated SystemTime="2026-07-17T09:54:44.930Z" />
<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 directory service object was undeleted -->
</EventData>
</Event>MITRE ATT&CK mapping
| ID | Technique | Tactic |
|---|---|---|
T1098 | Account Manipulation | Persistence |
T1562 | Impair Defenses | Defense Evasion |
Recommended actions
- Verify the identity of the undeleted object (`ObjectDN`) and confirm whether the restoration was part of an approved IT change request.