rundll32.exe

logsource:
  category: process_creation
  product: windows
detection:
  selection:
    - Image|endswith: '\rundll32.exe'
    - OriginalFileName: 'RUNDLL32.EXE'
  condition: selection

| tstats summariesonly=false count values(Processes.original_file_name) as original_file_name
    from datamodel=Endpoint.Processes
    where (Processes.original_file_name="RUNDLL32.EXE" OR Processes.process_name="rundll32.exe")
    by Processes.dest Processes.process_name Processes.process_path Processes.process
| rename Processes.* as *

DeviceProcessEvents
| where ProcessVersionInfoOriginalFileName in~ ("RUNDLL32.EXE")
    or FileName =~ "rundll32.exe"

process where event.type == "start" and
  (process.pe.original_file_name in~ ("RUNDLL32.EXE") or
   process.name : "rundll32.exe")

['rundll32.exe'].includes(String(OriginalFileName || '').toLowerCase())