title: Invoke-Obfuscation Via Use Rundll32
id: a5a30a6e-75ca-4233-8b8c-42e0f2037d3b
description: Detects Obfuscated Powershell via use Rundll32 in Scripts
status: experimental
author: Nikita Nazarov, oscd.community
date: 2019/10/08
references: 
    - https://github.com/Neo23x0/sigma/issues/1009
tags:
    - attack.defense_evasion
    - attack.t1027
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    service: powershell
detection:
    selection_1:
        EventID: 4104
    selection_2:
        - ScriptBlockText|re: '(?i).*downloadstring&&.*rundll32.*powershell.*(value|invoke|comspec|iex).*"'
    selection_3:
        EventID: 4103
    selection_4:
        - Payload|re: '(?i).*downloadstring&&.*rundll32.*powershell.*(value|invoke|comspec|iex).*"'
    condition: ( selection_1 and selection_2 ) or ( selection_3 and selection_4 )
falsepositives:
    - Unknown
level: high