WinEvent Scheduled Task Created to Spawn Shell

name: WinEvent Scheduled Task Created to Spawn Shell
id: 203ef0ea-9bd8-11eb-8201-acde48001122
version: 20
creation_date: '2021-04-08'
modification_date: '2026-05-13'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic detects the creation of scheduled tasks designed to execute commands using native Windows shells like PowerShell, Cmd, Wscript, or Cscript. It leverages Windows Security EventCode 4698 to identify when such tasks are registered. This activity is significant as it may indicate an attempt to establish persistence or execute malicious commands on a system. If confirmed malicious, this could allow an attacker to maintain access, execute arbitrary code, or escalate privileges, posing a severe threat to the environment.
data_source:
    - Windows Event Log Security 4698
search: |-
    `wineventlog_security` EventCode=4698 TaskContent IN ("*powershell.exe*", "*wscript.exe*", "*cscript.exe*", "*cmd.exe*", "*sh.exe*", "*ksh.exe*", "*zsh.exe*", "*bash.exe*", "*scrcons.exe*", "*pwsh.exe*")
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY Computer, TaskName, TaskContent
      | rename Computer as dest
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `winevent_scheduled_task_created_to_spawn_shell_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Windows Security Event Logs with 4698 EventCode enabled. The Windows TA is also required.
known_false_positives: False positives are possible if legitimate applications are allowed to register tasks that call a shell to be spawned. Filter as needed based on command-line or processes that are used legitimately.
references:
    - https://research.checkpoint.com/2021/irans-apt34-returns-with-an-updated-arsenal/
    - https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4698
    - https://redcanary.com/threat-detection-report/techniques/scheduled-task-job/
    - https://docs.microsoft.com/en-us/windows/win32/taskschd/time-trigger-example--scripting-?redirectedfrom=MSDN
finding:
    title: 'A Windows Scheduled Task was created (task name=$TaskName$) on $dest$ with the following contents: $TaskContent$'
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - CISA AA22-257A
    - China-Nexus Threat Activity
    - Compromised Windows Host
    - Medusa Ransomware
    - Ransomware
    - Ryuk Ransomware
    - Salt Typhoon
    - Scheduled Tasks
    - SystemBC
    - Windows Error Reporting Service Elevation of Privilege Vulnerability
    - Windows Persistence Techniques
    - Winter Vivern
    - 0bj3ctivity Stealer
    - Castle RAT
asset_type: Endpoint
mitre_attack_id:
    - T1053.005
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint