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Description

This analytic looks for the execution of at.exe with command-line arguments utilized to create a Scheduled Task on a remote endpoint. Red Teams and adversaries alike may abuse the Task Scheduler for lateral movement and remote code execution. The at.exe binary internally leverages the AT protocol which was deprecated starting with Windows 8 and Windows Server 2012 but may still work on previous versions of Windows. Furthermore, attackers may enable this protocol on demand by changing a sytem registry key.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-11-11
  • Author: Mauricio Velazco, Splunk
  • ID: 4be54858-432f-11ec-8209-3e22fbd008af

ATT&CK

ID Technique Tactic
T1053 Scheduled Task/Job Execution, Persistence, Privilege Escalation
T1053.002 At (Windows) Execution, Persistence, Privilege Escalation

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name=at.exe OR Processes.original_file_name=at.exe) (Processes.process=*\\\\*) by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| `scheduled_task_creation_on_remote_endpoint_using_at_filter`

Associated Analytic Story

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints.

Required field

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • Processes.parent_process_id

Kill Chain Phase

  • Lateral Movement

Known False Positives

Administrators may create scheduled tasks on remote systems, but this activity is usually limited to a small set of hosts or users.

RBA

Risk Score Impact Confidence Message
54.0 90 60 A Windows Scheduled Task was created on a remote endpoint from $dest

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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