Windows PowerShell Process Command Lines With Encoded Command Flags

Alerts on PowerShell (pwsh) command lines using encoded command flags and encoded-looking substrings, excluding gc_worker.exe-related activity.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-05-24
Updated: 2026-07-30

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 PowerShell or pwsh process creation events where the command line includes common encoded command options (e.g., -e/-enc) and additional command-line substrings typically seen in encoded payloads. Attackers often use encoded PowerShell to obscure script contents and evade simple command-line inspection. It relies on Windows process creation telemetry, matching Image/OriginalFileName for PowerShell and scanning CommandLine for the specified encoded patterns while excluding activity tied to a specific guest configuration worker process path.

Reporting behind it

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Windows PowerShell Process Command Lines With Encoded Command Flags

Pivot detection · T1059.001 · 9 related

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

windows-powershell-process-command-lines-with-encoded-command-flags-b9d9cc83

title: Windows PowerShell Process Command Lines With Encoded Command Flags
id: e44119d2-8ed1-456e-bf46-6b1b426263f3
status: test
description: This rule flags Windows PowerShell or pwsh process creation events where the command line includes common encoded command options (e.g., -e/-enc) and additional command-line substrings typically seen in encoded payloads. Attackers often use encoded PowerShell to obscure script contents and evade simple command-line inspection. It relies on Windows process creation telemetry, matching Image/OriginalFileName for PowerShell and scanning CommandLine for the specified encoded patterns while excluding activity tied to a specific guest configuration worker process path.
references:
  - https://app.any.run/tasks/b9040c63-c140-479b-ad59-f1bb56ce7a97/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_powershell_base64_encoded_cmd_patterns.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-05-24
modified: 2023-01-05
tags:
  - attack.execution
  - attack.t1059.001
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith:
        - \powershell.exe
        - \pwsh.exe
    - OriginalFileName:
        - PowerShell.Exe
        - pwsh.dll
  selection_flags:
    CommandLine|contains:
      - " -e "
      - " -en "
      - " -enc "
      - " -enco"
  selection_encoded:
    CommandLine|contains:
      - " JAB"
      - " SUVYI"
      - " SQBFAFgA"
      - " aWV4I"
      - " IAB"
      - " PAA"
      - " aQBlAHgA"
  filter_gcworker:
    ParentImage|contains:
      - C:\Packages\Plugins\Microsoft.GuestConfiguration.ConfigurationforWindows\
      - \gc_worker.exe
  condition: all of selection_* and not 1 of filter_*
falsepositives:
  - Other tools that work with encoded scripts in the command line instead of script files
level: high
license: DRL-1.1
related:
  - id: b9d9cc83-380b-4ba3-8d8f-60c0e7e2930c
    type: derived

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