Cross-Platform Detection of Scheduled Task/Job Abuse via `at` Utility

Technique Detected:  At | T1053.002

ID: DET0333
Domains: Enterprise
Analytics: AN0943, AN0944, AN0945
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN0943

Detects creation of scheduled tasks via at.exe or WMI Win32_ScheduledJob class, followed by execution of anomalous processes by svchost.exe or taskeng.exe.

Log Sources
Data Component Name Channel
Scheduled Job Creation (DC0001) WinEventLog:Security EventCode=4698
Process Creation (DC0032) WinEventLog:Sysmon EventCode=1
Mutable Elements
Field Description
TaskUser Unusual users creating jobs (e.g., non-admin accounts or service users).
ExecutionTimeWindow Delay between task registration and execution.
CommandLinePattern Unexpected script or binary execution (e.g., cmd.exe /c PowerShell payload).

AN0944

Detects usage of at command to schedule jobs, followed by job execution and modification of job files under /var/spool/cron/atjobs.

Log Sources
Data Component Name Channel
Process Creation (DC0032) auditd:SYSCALL execve
File Modification (DC0061) auditd:SYSCALL write
Mutable Elements
Field Description
AtJobPath Monitoring additional paths (e.g., tmp-mounted spool dirs) for modified at jobs.
ScheduleLatency Expected delay between at job creation and execution.
JobScriptEntropy High entropy or obfuscation in at job payloads.

AN0945

Detects user or root invocation of at command to schedule a job, followed by job execution using LaunchServices and activity in /usr/lib/cron/at.

Log Sources
Data Component Name Channel
Command Execution (DC0064) macos:unifiedlog process: at, job runner
File Modification (DC0061) fs:fsusage file access to /usr/lib/cron/at and job execution path
Process Creation (DC0032) macos:osquery process_events
Mutable Elements
Field Description
AtPermissions Whether `at.allow` and `at.deny` are properly configured.
ExecutionCommand Target binary executed via the at job.
RunUser Detection of root user scheduling job with unusual command.