Windows: MSOHTMED.EXE Arbitrary File Download Using HTTP/FTP URLs

title: "Windows: MSOHTMED.EXE Arbitrary File Download Using HTTP/FTP URLs"
id: 41eac809-8d1a-4c6d-99e5-219cf5115a72
status: test
description: This rule flags process creation where MSOHTMED.EXE (identified by filename and OriginalFileName) is launched with a command line containing HTTP or FTP URLs. Attackers can use this behavior to retrieve arbitrary payloads or stage additional components while blending into normal Windows execution patterns. The detection relies on Windows process creation telemetry including Image path, OriginalFileName, and CommandLine content.
references:
  - https://github.com/LOLBAS-Project/LOLBAS/pull/238/files
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_msohtmed_download.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-08-19
modified: 2023-11-09
tags:
  - attack.execution
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \MSOHTMED.exe
    - OriginalFileName: MsoHtmEd.exe
  selection_cli:
    CommandLine|contains:
      - ftp://
      - http://
      - https://
  condition: all of selection_*
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 459f2f98-397b-4a4a-9f47-6a5ec2f1c69d
    type: derived