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Invoke-Obfuscation VAR+ Launcher - PowerShell

Detects Obfuscated use of Environment Variables to execute PowerShell

MITRE ATT&CK

defense-evasionexecution

Detection Query

selection_4104:
  ScriptBlockText|re: cmd.{0,5}(?:/c|/r)(?:\s|)"set\s[a-zA-Z]{3,6}.*(?:\{\d\}){1,}\\"\s+?-f(?:.*\)){1,}.*"
condition: selection_4104

Author

Jonathan Cheong, oscd.community

Created

2020-10-15

Data Sources

windowsps_script

Platforms

windows

References

https://github.com/SigmaHQ/sigma/issues/1009

Tags

attack.defense-evasionattack.t1027attack.executionattack.t1059.001

Raw Content

title: Invoke-Obfuscation VAR+ Launcher - PowerShell
id: 0adfbc14-0ed1-11eb-adc1-0242ac120002
status: test
description: Detects Obfuscated use of Environment Variables to execute PowerShell
references:
    - https://github.com/SigmaHQ/sigma/issues/1009  # (Task 24)
author: Jonathan Cheong, oscd.community
date: 2020-10-15
modified: 2024-04-05
tags:
    - attack.defense-evasion
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_4104:
        ScriptBlockText|re: 'cmd.{0,5}(?:/c|/r)(?:\s|)"set\s[a-zA-Z]{3,6}.*(?:\{\d\}){1,}\\"\s+?-f(?:.*\)){1,}.*"'
    condition: selection_4104
falsepositives:
    - Unknown
level: high