Direct answer
Event 4624 records a successful logon session on the accessed computer. Review the account, logon type, time and available source context before deciding whether the session was expected.
Understand the session type
Microsoft documents logon types including interactive, network and batch. The type describes how a session was created; it does not alone establish that a human sat at the keyboard or that the activity was authorized. Check the device role and how its applications normally authenticate.
Reference: Microsoft: Security event 4624.
Collect the right context
Record device, event time, target account, logon type and logon ID in a restricted investigation. Correlate matching session identifiers on the same device with related events while checking clock accuracy and collection gaps. Fields can be unavailable depending on the logon path.
Compare expected behavior
For an unexpected network logon to a workstation, ask whether a support tool or file-sharing workflow normally uses that account from the reported source. Verify the owner, support schedule and related network records rather than assuming that a successful authentication means permission was appropriate.
Escalate and preserve evidence
Escalate unexplained sessions under the incident plan and preserve the original events and uncertainty. Do not disable a shared service account without coordinating dependencies and incident containment. Document the investigation result and any device or account that could not be checked.
Assessment limits
A successful logon does not prove subsequent actions were authorized. Logon IDs are local to the relevant context and should not be treated as universal identifiers across devices.
Frequently asked questions
Does a successful logon prove activity was legitimate?
No. Compare the identity, source, session type and activity with expected behavior.
Does every 4624 represent an interactive user?
No. Windows records network and batch sessions as well as interactive sessions.
Primary sources and further reading
These guides combine published security guidance with practical assessment planning. Adapt checks to the owner's policy, environment, and authorized scope.
This guide was prepared with AI assistance using the linked sources and illustrative examples. Check current vendor guidance and your environment before making changes.