PowerShell Module: Obfuscated STDIN Execution via cmd /c or cmd /r

Alerts when an obfuscated cmd->PowerShell payload uses stdin-style input and noexit/no-execution patterns.

FreeReviewedSigma · High · v2

Product: windows
Category: ps_module
Author: Jonathan Cheong, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-15
Updated: 2026-07-31

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies PowerShell module activity where an obfuscated command line uses cmd with /c or /r and includes PowerShell invocation that reads input from stdin (e.g., ${input} or $input) or related no-exit patterns. Attackers may use this technique to hide payload intent and deliver commands through stdin, complicating analysis and filtering. The detection relies on telemetry capturing the PowerShell module payload or command text and matching it against the specified obfuscation and stdin-based execution pattern.

Reporting behind it

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PowerShell Module: Obfuscated STDIN Execution via cmd /c or cmd /r

Pivot detection · T1027 · 9 related

Changelog

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.

powershell-module-obfuscated-stdin-based-launcher-execution-9ac8b09b

title: "PowerShell Module: Obfuscated STDIN Execution via cmd /c or cmd /r"
id: 1852384a-6cbb-4a77-895a-ebdf4b5c4eff
related:
  - id: 779c8c12-0eb1-11eb-adc1-0242ac120002
    type: derived
  - id: 9ac8b09b-45de-4a07-9da1-0de8c09304a3
    type: derived
status: test
description: This rule identifies PowerShell module activity where an obfuscated command line uses cmd with /c or /r and includes PowerShell invocation that reads input from stdin (e.g., ${input} or $input) or related no-exit patterns. Attackers may use this technique to hide payload intent and deliver commands through stdin, complicating analysis and filtering. The detection relies on telemetry capturing the PowerShell module payload or command text and matching it against the specified obfuscation and stdin-based execution pattern.
references:
  - https://github.com/SigmaHQ/sigma/issues/1009
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_module/posh_pm_invoke_obfuscation_stdin.yml
author: Jonathan Cheong, oscd.community, Huntrule Team
date: 2020-10-15
modified: 2024-04-05
tags:
  - attack.stealth
  - attack.t1027
  - attack.execution
  - attack.t1059.001
logsource:
  product: windows
  category: ps_module
  definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b
detection:
  selection_4103:
    Payload|re: cmd.{0,5}(?:/c|/r).+powershell.+(?:\$\{?input\}?|noexit).+"
  condition: selection_4103
falsepositives:
  - Unknown
level: high
license: DRL-1.1

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

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