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Detection rules › Sigma

Invoke-Obfuscation Via Stdin

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Nikita Nazarov, oscd.community
Source
github.com/SigmaHQ/sigma

Detects Obfuscated Powershell via Stdin in Scripts

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell
StealthT1027 Obfuscated Files or Information

Event coverage

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

Rule body yaml

title: Invoke-Obfuscation Via Stdin
id: 9c14c9fa-1a63-4a64-8e57-d19280559490
status: test
description: Detects Obfuscated Powershell via Stdin in Scripts
references:
    - https://github.com/SigmaHQ/sigma/issues/1009 # (Task28)
author: Nikita Nazarov, oscd.community
date: 2020-10-12
modified: 2026-03-16
tags:
    - attack.stealth
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|re: '(?i)(?:set).*&&\s?set.*(?:environment|invoke|\$\{?input).*&&.*"'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    CommandLine|re: '(?i)(?:set).*&&\s?set.*(?:environment|invoke|\$\{?input).*&&.*"'

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
CommandLineregex_match
  • (?i)(?:set).*&&\s?set.*(?:environment|invoke|${?input).*&&.*"