SigmaHQ/rules/windows/builtin/win_invoke_obfuscation_obfuscated_iex_services.yml

action: global
title: Invoke-Obfuscation Obfuscated IEX Invocation
id: 51aa9387-1c53-4153-91cc-d73c59ae1ca9
description: "Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the following code block \u2014 https://github.com/danielbohannon/Invoke-Obfuscation/blob/master/Out-ObfuscatedStringCommand.ps1#L873-L888"
status: experimental
author: Daniel Bohannon (@Mandiant/@FireEye), oscd.community
date: 2019/11/08
tags:
    - attack.defense_evasion
    - attack.t1027
falsepositives:
    - Unknown
level: high
detection:
    selection_1:
        - ImagePath|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
        - ImagePath|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
        - ImagePath|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
        - ImagePath|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
        - ImagePath|re: '\*mdr\*\W\s*\)\.Name'
        - ImagePath|re: '\$VerbosePreference\.ToString\('
        - ImagePath|re: '\String\]\s*\$VerbosePreference'
    condition: selection and selection_1
---
logsource:
    product: windows
    service: system
detection:
    selection:
        EventID: 7045
---
logsource:
    product: windows
    service: sysmon
detection:
    selection:
        EventID: 6
---
 logsource:
     product: windows
     service: security
 detection:
     selection:
         EventID: 4697