PowerShell Obfuscated stdin launcher using cmd /c or cmd /r patterns

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 flags PowerShell script block content that matches obfuscated execution patterns involving cmd /c or cmd /r and PowerShell invocation that references stdin (input) with variations such as {input} or noexit. Attackers may use stdin-based launching and command-line indirection to conceal execution and evade simpler detections. It relies on PowerShell Script Block Logging telemetry capturing the script block text for pattern matches.

Reporting behind it

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PowerShell Obfuscated stdin launcher using cmd /c or cmd /r patterns

Pivot detection · T1027 · 9 related

Changelog

v2

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-script-block-obfuscation-via-stdin-execution-patterns-779c8c12

title: PowerShell Obfuscated stdin launcher using cmd /c or cmd /r patterns
id: d8e8f341-b49c-4711-9f76-a47cea95b3f9
status: test
description: This rule flags PowerShell script block content that matches obfuscated execution patterns involving cmd /c or cmd /r and PowerShell invocation that references stdin (input) with variations such as {input} or noexit. Attackers may use stdin-based launching and command-line indirection to conceal execution and evade simpler detections. It relies on PowerShell Script Block Logging telemetry capturing the script block text for pattern matches.
references:
  - https://github.com/SigmaHQ/sigma/issues/1009
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/powershell/powershell_script/posh_ps_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_script
  definition: "Requirements: Script Block Logging must be enabled"
detection:
  selection_4104:
    ScriptBlockText|re: cmd.{0,5}(?:/c|/r).+powershell.+(?:\$?\{?input\}?|noexit).+"
  condition: selection_4104
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 779c8c12-0eb1-11eb-adc1-0242ac120002
    type: derived

Convert

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

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