Invoke-Obfuscation Obfuscated IEX Invocation - PowerShell

Title: Invoke-Obfuscation Obfuscated IEX Invocation - PowerShell
Status: test
Description:Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the following code block \u2014
References:
  -https://github.com/danielbohannon/Invoke-Obfuscation/blob/f20e7f843edd0a3a7716736e9eddfa423395dd26/Out-ObfuscatedStringCommand.ps1#L873-L888
Author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
Date: 2019-11-08
modified:2022-12-31
Tags:

• -'attack.stealth'
• -'attack.t1027'
• -'attack.execution'
• -'attack.t1059.001'

Logsource:

• product: windows
• category: ps_script
• definition: Requirements: Script Block Logging must be enabled

Detection:
  selection_iex:
ScriptBlockText|re:'\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\[' ScriptBlockText|re:'\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\[' ScriptBlockText|re:'\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\[' ScriptBlockText|re:'\$env:ComSpec\[(\s*\d{1,3}\s*,){2}' ScriptBlockText|re:'\*mdr\*\W\s*\)\.Name' ScriptBlockText|re:'\$VerbosePreference\.ToString\('   condition:selection_iex
Falsepositives:
  -Unknown
Level: high