LoFP / false positives may arise from legitimate applications that create tasks to run as system. therefore, it's recommended to adjust filters based on parent process or modify the query to include world writable paths for restriction.

Techniques

• T1053
• T1053.005

Sample rules

Windows Scheduled Task with Highest Privileges

• source: splunk
• technicques:
  • T1053
  • T1053.005

Description

The following analytic detects the creation of a new scheduled task with the highest execution privileges via Schtasks.exe. It leverages Endpoint Detection and Response (EDR) logs to monitor for specific command-line parameters (’/rl’ and ‘highest’) in schtasks.exe executions. This activity is significant as it is commonly used in AsyncRAT attacks for persistence and privilege escalation. If confirmed malicious, this could allow an attacker to maintain persistent access and execute tasks with elevated privileges, potentially leading to unauthorized system access and data breaches.

Detection logic

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime  from datamodel=Endpoint.Processes where Processes.process_name = "schtasks.exe" Processes.process = "*/rl *" Processes.process = "* highest *" by Processes.process_name Processes.parent_process_name Processes.parent_process Processes.process Processes.process_guid Processes.dest Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_scheduled_task_with_highest_privileges_filter`