Windows Process Execution Using Obfuscated CMD to Pipe STDIN into PowerShell

Detects obfuscated cmd executions that launch PowerShell and reference $input/noexit patterns for STDIN-based execution.

FreeReviewedSigma · High · v2

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

Analysis Detection

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 Windows process executions where an obfuscated cmd command invokes PowerShell while referencing an input stream such as ${input} or -NoExit, consistent with stdin-based launcher behavior. Attackers can use this pattern to hide execution details and dynamically feed commands to PowerShell to reduce detection visibility. The detection relies on process creation telemetry, specifically the CommandLine field matching an obfuscation-tolerant pattern for cmd and PowerShell interaction with input.

Reporting behind it

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Windows Process Execution Using Obfuscated CMD to Pipe STDIN into PowerShell

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.

windows-process-creation-obfuscated-cmd-launcher-using-powershell-with-stdin-inp-6c96fc76

title: Windows Process Execution Using Obfuscated CMD to Pipe STDIN into PowerShell
id: 871e3c2a-5f09-4dc9-b68c-f5a30de9bb26
status: test
description: This rule identifies Windows process executions where an obfuscated cmd command invokes PowerShell while referencing an input stream such as ${input} or -NoExit, consistent with stdin-based launcher behavior. Attackers can use this pattern to hide execution details and dynamically feed commands to PowerShell to reduce detection visibility. The detection relies on process creation telemetry, specifically the CommandLine field matching an obfuscation-tolerant pattern for cmd and PowerShell interaction with input.
references:
  - https://github.com/SigmaHQ/sigma/issues/1009
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_hktl_invoke_obfuscation_stdin.yml
author: Jonathan Cheong, oscd.community, Huntrule Team
date: 2020-10-15
modified: 2024-04-15
tags:
  - attack.stealth
  - attack.t1027
  - attack.execution
  - attack.t1059.001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    CommandLine|re: cmd.{0,5}(?:/c|/r).+powershell.+(?:\$\{?input\}?|noexit).+\"
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 6c96fc76-0eb1-11eb-adc1-0242ac120002
    type: derived

Convert

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

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