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

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

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.

Reporting behind it

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

Pivot detection · T1218 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-msohtmed-exe-arbitrary-file-download-using-http-ftp-urls-459f2f98

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

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