Windows dllhost.exe Spawn Without Command-Line Arguments

title: Windows dllhost.exe Spawn Without Command-Line Arguments
id: 41e8550b-52ee-443f-81a4-b6ec0861b2dc
status: test
description: This rule flags Windows process creation events where an executable ending in dllhost.exe is launched with a null/empty command line. Legitimate launches of dllhost with no arguments are rare, and this pattern can indicate stealthy execution such as injected or spoofed payloads masquerading as a system component. The detection relies on Windows process creation telemetry, specifically the process image path and captured command-line content.
references:
  - https://redcanary.com/blog/child-processes/
  - https://nasbench.medium.com/what-is-the-dllhost-exe-process-actually-running-ef9fe4c19c08
  - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/goofy-guineapig/NCSC-MAR-Goofy-Guineapig.pdf
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_dllhost_no_cli_execution.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-06-27
modified: 2023-05-15
tags:
  - attack.privilege-escalation
  - attack.stealth
  - attack.t1055
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: \dllhost.exe
    CommandLine:
      - dllhost.exe
      - dllhost
  filter_main_null:
    CommandLine: null
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: e7888eb1-13b0-4616-bd99-4bc0c2b054b9
    type: derived