Outbound Scheduled Task Activity via PowerShelledit

Identifies the PowerShell process loading the Task Scheduler COM DLL followed by an outbound RPC network connection within a short time period. This may indicate lateral movement or remote discovery via scheduled tasks.

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

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

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 positivesedit

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

Rule queryedit

sequence by host.id, process.entity_id with maxspan = 5s [library
where dll.name : "taskschd.dll" and process.name : ("powershell.exe",
"pwsh.exe")] [network where process.name : ("powershell.exe",
"pwsh.exe") and destination.port == 135 and not destination.address in
("127.0.0.1", "::1")]

Threat mappingedit

Framework: MITRE ATT&CKTM

Rule version historyedit

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

    sequence by host.id, process.entity_id with maxspan = 5s [library
    where file.name: "taskschd.dll" and process.name: ("powershell.exe",
    "pwsh.exe")] [network where process.name : ("powershell.exe",
    "pwsh.exe") and destination.port == 135 and not destination.address in
    ("127.0.0.1", "::1")]