Suspicious Rundll32 Spawned Through Explorer.EXE (via process_creation)

title: Suspicious Rundll32 Spawned Through Explorer.EXE (via process_creation)
id: 0bf53948-b29f-5f50-baa0-764daf1acdf3
status: stable
description: This rule detects execution of "rundll32.exe" with a parent process of Explorer.exe. This has been observed by variants of Raspberry Robin, as first reported by Red Canary.
references:
    - https://redcanary.com/blog/raspberry-robin/
    - https://thedfirreport.com/2022/09/26/bumblebee-round-two/
author: Huntrule Team
date: 2026-07-13
tags:
    - attack.stealth
    - attack.defense-evasion
    - attack.t1218.011
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\explorer.exe'
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    filter_main_generic:
        - CommandLine|contains: ' C:\Windows\System32\'
        - CommandLine|endswith: ' -localserver 22d8c27b-47a1-48d1-ad08-7da7abd79617'
    condition: all of selection_* and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium