4801 Security log · Logon/Logoff info severity high volume

Windows Event ID 4801 — The workstation was unlocked

Workstation unlocked. Off-hours unlocks on sensitive systems warrant review.

Why event 4801 matters

Alert on off-hours unlocks on server or admin workstations.

How to detect it

Alert: 4801 at unusual hours (2–5 AM) for sensitive workstations. Correlate with physical access logs.

Log source
Security
Advanced Audit Policy — enable the 'Logon/Logoff' subcategory (Success and/or Failure).
Fields to pivot on
SubjectUserNameTargetUserNameLogonTypeIpAddressWorkstationName

Detection queries

Starting points — adapt the log source, projected fields and thresholds for your environment.

Sentinel / Defender KQL
SecurityEvent
| where EventID == 4801   // The workstation was unlocked
| project TimeGenerated, Computer, SubjectUserName, TargetUserName, LogonType, IpAddress, WorkstationName
| sort by TimeGenerated desc
Splunk SPL
index=* sourcetype="WinEventLog:Security" EventCode=4801
| stats count earliest(_time) as first_seen latest(_time) as last_seen by ComputerName
| sort - count   `# The workstation was unlocked — add EventData fields: SubjectUserName, TargetUserName, LogonType, IpAddress`
Hunt event 4801 in Sentinel/Defender →
Build a KQL query for this event in the KQL Query Builder.
Search all event IDs →
Open the interactive Windows Event ID lookup.

Related Logon/Logoff events

4624 An account was successfully logged on 4625 An account failed to log on 4626 User/Device claims information 4627 Group membership information 4634 An account was logged off 4647 User initiated logoff 4648 A logon was attempted using explicit credentials 4649 A replay attack was detected 4672 Special privileges assigned to new logon 4778 A session was reconnected to a Window Station 4779 A session was disconnected from a Window Station 4800 The workstation was locked

Frequently asked questions

What is Windows Event ID 4801?

The workstation was unlocked. Workstation unlocked. Off-hours unlocks on sensitive systems warrant review.

Which log records event 4801?

Event 4801 is written to the Security channel by Microsoft-Windows-Security-Auditing. Advanced Audit Policy — enable the 'Logon/Logoff' subcategory (Success and/or Failure).

How do you detect activity around event 4801?

Alert: 4801 at unusual hours (2–5 AM) for sensitive workstations. Correlate with physical access logs.