A registry value was modified
A registry key value was created, altered, or deleted within an audited registry path.
Event ID 4657 captures granular modifications to registry values (`Object Type: Key`) when a System Access Control List (SACL) is applied. It logs the exact registry key path, the old value, the new value, and the process (`ProcessName`) causing the change.
Failure Reason / Root Cause:
Registry modification on an audited key (e.g., Run keys, LSA configurations, Service keys).
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>4657</EventID>
<Version>0</Version>
<Level>0</Level>
<Task>12544</Task>
<Opcode>0</Opcode>
<Keywords>0x8020000000000000</Keywords>
<TimeCreated SystemTime="2026-07-17T09:54:44.869Z" />
<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 registry value was modified -->
</EventData>
</Event>MITRE ATT&CK mapping
| ID | Technique | Tactic |
|---|---|---|
T1547.001 | Registry Run Keys / Startup Folder | Persistence |
T1112 | Modify Registry | Defense Evasion |
Recommended actions
- Inspect the `ProcessName` and check whether the modified key establishes persistence (`HKLM\Software\Microsoft\Windows\CurrentVersion\Run`).
- Correlate with process creation event `4688`.