Windows Process Creation: Detect Reversed PowerShell Command Tokens in CommandLine

Alerts on suspicious reversed token usage in PowerShell command lines on Windows, excluding -EncodedCommand / -enc.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Teymur Kheirkhabarov (idea), Vasiliy Burov (rule), oscd.community, Tim Shelton (SigmaHQ), DRL 1.1
Published: 2020-10-11
Updated: 2026-07-30

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 Windows process creation events where PowerShell (powershell.exe or pwsh.exe) is launched with CommandLine content containing specific reversed-character tokens. Reversed strings are commonly used to obscure what the script is doing and may hinder straightforward command inspection. The detection relies on process creation telemetry and the Image and CommandLine fields, while excluding cases that include common encoded-command flags to reduce false positives.

Reporting behind it

Related detections9 linkedT1027 — drag to rearrange

Suspicious PowerShell Invoke-Expression with Replace Obfuscation

Malicious Emmenhtal JavaScript Loader Spawning Encoded PowerShell

Suspicious Python Interpreter Launching Encoded PowerShell via subprocess

Suspicious PS1Bot PowerShell Payload Written to ProgramData (via file_event)

Malicious Non-Interactive Encoded PowerShell Stager (via process_creation)

Suspicious Hidden PowerShell Executing Substring of Dropped File

PowerShell Encoded or Download-Cradle Command Line (via process_creation)

Obfuscated Encoded PowerShell Payload Deployed - PowerShell (via powershell)

Suspicious PowerShell AES Decryption and Reflective Method Invocation in SolarMarker

Windows Process Creation: Detect Reversed PowerShell Command Tokens in CommandLine

Pivot detection · T1027 · 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-process-creation-detect-reversed-powershell-command-tokens-in-commandlin-b6b49cd1

title: "Windows Process Creation: Detect Reversed PowerShell Command Tokens in CommandLine"
id: ecb0a7db-4265-4e57-bfe6-32574348d682
status: test
description: This rule flags Windows process creation events where PowerShell (powershell.exe or pwsh.exe) is launched with CommandLine content containing specific reversed-character tokens. Reversed strings are commonly used to obscure what the script is doing and may hinder straightforward command inspection. The detection relies on process creation telemetry and the Image and CommandLine fields, while excluding cases that include common encoded-command flags to reduce false positives.
references:
  - https://2019.offzone.moscow/ru/report/hunting-for-powershell-abuses/
  - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=66
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_powershell_cmdline_reversed_strings.yml
author: Teymur Kheirkhabarov (idea), Vasiliy Burov (rule), oscd.community, Tim Shelton, Huntrule Team
date: 2020-10-11
modified: 2023-05-31
tags:
  - attack.stealth
  - attack.t1027
  - 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_cli:
    CommandLine|contains:
      - hctac
      - kaerb
      - dnammoc
      - ekovn
      - eliFd
      - rahc
      - etirw
      - golon
      - tninon
      - eddih
      - tpircS
      - ssecorp
      - llehsrewop
      - esnopser
      - daolnwod
      - tneilCbeW
      - tneilc
      - ptth
      - elifotevas
      - 46esab
      - htaPpmeTteG
      - tcejbO
      - maerts
      - hcaerof
      - retupmoc
  filter_main_encoded_keyword:
    CommandLine|contains:
      - " -EncodedCommand "
      - " -enc "
  condition: all of selection_* and not 1 of filter_main_*
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: b6b49cd1-34d6-4ead-b1bf-176e9edba9a4
    type: derived

Convert

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

SplunkSPL