Scheduled Task Created by a Windows Script

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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.*
  • logs-windows.*
  • 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

Version: 105

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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## Triage and analysis

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

Rule query

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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 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&CKTM