
title: Invoke-Obfuscation Obfuscated IEX Invocation
author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
date: 2019/11/08
description: Detects all variations of obfuscated powershell IEX invocation code generated
  by Invoke-Obfuscation framework from the following code block — https://github.com/danielbohannon/Invoke-Obfuscation/blob/master/Out-ObfuscatedStringCommand.ps1#L873-L888
detection:
  SELECTION_1:
    Payload|re: \$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\[
  SELECTION_2:
    Payload|re: \$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\[
  SELECTION_3:
    Payload|re: \$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\[
  SELECTION_4:
    Payload|re: \$env:ComSpec\[(\s*\d{1,3}\s*,){2}
  SELECTION_5:
    Payload|re: \\\\*mdr\\\\*\W\s*\)\.Name
  SELECTION_6:
    Payload|re: \$VerbosePreference\.ToString\(
  SELECTION_7:
    Payload|re: \String\]\s*\$VerbosePreference
  condition: (SELECTION_1 or SELECTION_2 or SELECTION_3 or SELECTION_4 or SELECTION_5
    or SELECTION_6 or SELECTION_7)
falsepositives:
- Unknown
id: 2f211361-7dce-442d-b78a-c04039677378
level: high
logsource:
  category: ps_module
  definition: PowerShell Module Logging must be enabled
  product: windows
modified: 2021/10/16
related:
- id: 1b9dc62e-6e9e-42a3-8990-94d7a10007f7
  type: derived
status: experimental
tags:
- attack.defense_evasion
- attack.t1027
- attack.execution
- attack.t1059.001
- attack.t1086
ruletype: SIGMA
