Scheduled Task Created by a Windows Script

edit

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.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

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

Maximum alerts per execution: 100

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Persistence

Version: 2 (version history)

Added (Elastic Stack release): 7.11.0

Last modified (Elastic Stack release): 7.12.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

edit

Legitimate scheduled tasks may be created during installation of new software.

Investigation guide

edit

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 [library where dll.name :
"taskschd.dll" and process.name : ("cscript.exe", "wscript.exe",
"powershell.exe")] [registry where registry.path :
"HKLM\\SOFTWARE\\Microsoft\\Windows
NT\\CurrentVersion\\Schedule\\TaskCache\\Tasks\\*\\Actions"]

Threat mapping

edit

Framework: MITRE ATT&CKTM

Rule version history

edit
Version 2 (7.12.0 release)
  • Updated query, changed from:

    sequence by host.id with maxspan = 30s [library where file.name :
    "taskschd.dll" and process.name : ("cscript.exe", "wscript.exe",
    "powershell.exe")] [registry where registry.path :
    "HKLM\\SOFTWARE\\Microsoft\\Windows
    NT\\CurrentVersion\\Schedule\\TaskCache\\Tasks\\*\\Actions"]