Task Scheduler Operational Log

The TaskScheduler/Operational event log channel provides detailed tracing of scheduled tasks on an endpoint.

Analysis Value

Command Line OptionsFirst ExecutedLast ExecutedEvidence of ExecutionExecution TimestampFile PathSource Identification

Operating System Availability

Major Version	Support	Major Version	Support
Windows 11	✅	Server 2019	✅
Windows 10	✅	Server 2016	✅
Windows 8	✅	Server 2012	✅
Windows 7	✅	Server 2008	✅
Windows Vista	❌	Server 2003	❌
Windows XP	❌

Artifact Location(s)

• %SystemRoot%\System32\Winevt\Logs\Microsoft-Windows-TaskScheduler%4Operational.evtx

Artifact Interpretation

The following event IDs are useful to hunt for persistent implants on an endpoint:

Event ID	Description	Information
106	Scheduled Task Created	Origin Account/User
140	Scheduled Task Updated	Origin Account/User
141	Scheduled Task Deleted	Origin Account/User
200	Scheduled Task Executed	Executable file path
201	Scheduled Task Execution Completed	Executable file path

This activity is also logged in the Security channel with more granular information, as follows:

Event ID	Description
4698	Scheduled Task Created
4702	Scheduled Task Updated
4699	Scheduled Task Deleted

Caveats

Logging for these events is disabled by default and must be enabled to provide these artifacts.

Analysis Tips

Deleted Scheduled Tasks

Scheduled task deletion is a rare event on Windows systems and provides an easy to query, high-fidelity indicator of suspicious activity. The following event IDs may be queried:

• Windows-TaskScheduler\Operational Event 141: Scheduled Task Deleted

• Security Event 4699: Scheduled Task Deleted

Software Installation/Uninstallation

When applications are installed on a Windows system, they will sometimes create a scheduled task to run their update functionality, making the Task Scheduler Operational log a possible option for cross-validation of other application installation artifacts such as the Uninstall registry key.

Lateral Movement through Remote Scheduled Task Installation

In the event that tasks are remotely scheduled, as is commonly seen during lateral movement attempts, this activity may be identified by observing Type 3 logons via EventID 4624: An account was successfully logged on events in close proximity to task creation.