Suspicious Child Process Spawning by PowerShell on Windows

Alerts when PowerShell spawns potentially suspicious child binaries (e.g., certutil, mshta, wmic, rundll32), with exclusions for known benign patterns.

FreeReviewedSigma · Medium · v4

Product: windows
Category: process_creation
Author: Florian Roth (Nextron Systems), Tim Shelton (SigmaHQ), DRL 1.1
Published: 2022-04-26
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows process creation events where PowerShell (powershell.exe, pwsh.exe, or powershell_ise.exe) launches a set of potentially suspicious child executables. Attackers commonly chain PowerShell to other living-off-the-land binaries to execute actions, stage payloads, or proxy execution while reducing direct tool visibility. It relies on telemetry that records process creation with parent and image paths plus command lines to support optional exclusions for known script locations and specific certutil/wmic usage patterns.

Reporting behind it

Related detections9 linkedT1059.001 — drag to rearrange

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Suspicious PowerShell WebClient DownloadFile of Archive Payload (UAT-7237)

Suspicious SharePoint Worker Process Spawning Command Interpreter via ToolShell

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Suspicious Python Interpreter Launching Encoded PowerShell via subprocess

Suspicious Child Process Spawning by PowerShell on Windows

Pivot detection · T1059.001 · 9 related

Changelog

v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

suspicious-windows-powershell-child-processes-spawned-by-powershell-exe-pwsh-exe-e4b6d2a7

title: Suspicious Child Process Spawning by PowerShell on Windows
id: 8e0cdcdc-8b18-4a0b-9a4e-ccb8297d6319
status: test
description: This rule flags Windows process creation events where PowerShell (powershell.exe, pwsh.exe, or powershell_ise.exe) launches a set of potentially suspicious child executables. Attackers commonly chain PowerShell to other living-off-the-land binaries to execute actions, stage payloads, or proxy execution while reducing direct tool visibility. It relies on telemetry that records process creation with parent and image paths plus command lines to support optional exclusions for known script locations and specific certutil/wmic usage patterns.
references:
  - https://twitter.com/ankit_anubhav/status/1518835408502620162
  - https://github.com/SigmaHQ/sigma/blob/master/rules-threat-hunting/windows/process_creation/proc_creation_win_powershell_susp_child_processes.yml
author: Florian Roth (Nextron Systems), Tim Shelton, Huntrule Team
date: 2022-04-26
modified: 2024-07-16
tags:
  - attack.execution
  - attack.t1059.001
  - detection.threat-hunting
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith:
      - \powershell_ise.exe
      - \powershell.exe
      - \pwsh.exe
    Image|endswith:
      - \bash.exe
      - \bitsadmin.exe
      - \certutil.exe
      - \cscript.exe
      - \forfiles.exe
      - \hh.exe
      - \mshta.exe
      - \regsvr32.exe
      - \rundll32.exe
      - \schtasks.exe
      - \scrcons.exe
      - \scriptrunner.exe
      - \sh.exe
      - \wmic.exe
      - \wscript.exe
  filter_optional_amazon:
    ParentCommandLine|contains: \Program Files\Amazon\WorkspacesConfig\Scripts\
    CommandLine|contains: \Program Files\Amazon\WorkspacesConfig\Scripts\
  filter_main_certutil_verify_store:
    Image|endswith: \certutil.exe
    CommandLine|contains: "-verifystore "
  filter_main_wmic:
    Image|endswith: \wmic.exe
    CommandLine|contains:
      - qfe list
      - "diskdrive "
      - "csproduct "
      - "computersystem "
      - " os "
      - ""
  condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
  - False positives are to be expected from PowerShell scripts that might make use of additional binaries such as "mshta", "bitsadmin", etc. Apply additional filters for those scripts.
level: medium
license: DRL-1.1
related:
  - id: e4b6d2a7-d8a4-4f19-acbd-943c16d90647
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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