Scheduled Task Created by a Windows Script

A scheduled task was created by a Windows script via cscript.exe, wscript.exe or powershell.exe. This can be abused by an adversary to establish persistence.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.registry-*
logs-endpoint.events.library-*
logs-windows.sysmon_operational-*
endgame-*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Persistence
Tactic: Execution
Data Source: Elastic Endgame
Data Source: Elastic Defend
Data Source: Sysmon

Version: 108

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

edit

Triage and analysis

Decode the base64 encoded Tasks Actions registry value to investigate the task’s configured action.

Rule query

edit

sequence by host.id with maxspan = 30s
  [any where host.os.type == "windows" and
    (event.category : ("library", "driver") or (event.category == "process" and event.action : "Image loaded*")) and
    (?dll.name : "taskschd.dll" or file.name : "taskschd.dll") and
    process.name : ("cscript.exe", "wscript.exe", "powershell.exe", "pwsh.exe", "powershell_ise.exe")]
  [registry where host.os.type == "windows" and event.type == "change" and registry.value : "Actions" and
    registry.path : (
      "HKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Schedule\\TaskCache\\Tasks\\*\\Actions",
      "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Schedule\\TaskCache\\Tasks\\*\\Actions"
  )]

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
Technique:
- Name: Scheduled Task/Job
- ID: T1053
- Reference URL: https://attack.mitre.org/techniques/T1053/
Sub-technique:
- Name: Scheduled Task
- ID: T1053.005
- Reference URL: https://attack.mitre.org/techniques/T1053/005/
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
Sub-technique:
- Name: PowerShell
- ID: T1059.001
- Reference URL: https://attack.mitre.org/techniques/T1059/001/
Sub-technique:
- Name: Visual Basic
- ID: T1059.005
- Reference URL: https://attack.mitre.org/techniques/T1059/005/

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