Windows ProtocolHandler.exe Download via Embedded URL Schemes

Flags ProtocolHandler.exe executions with ftp/http/https URLs that indicate automated downloading on Windows.

FreeReviewedSigma · Medium · v1

Product: windows
Category: process_creation
Author: frack113 (SigmaHQ), DRL 1.1
Published: 2021-07-13
Updated: 2026-07-30

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 identifies process executions of ProtocolHandler.exe where the command line contains URL schemes (ftp://, http://, or https://), indicating a file download attempt using the ProtocolHandler binary. Attackers can abuse signed Windows components to fetch external content while blending into normal system behavior. The detection relies on Windows process creation telemetry, matching the executable identity and the presence of these URL schemes in the command line.

Reporting behind it

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Windows ProtocolHandler.exe Download via Embedded URL Schemes

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-protocolhandler-exe-download-via-embedded-url-schemes-104cdb48

title: Windows ProtocolHandler.exe Download via Embedded URL Schemes
id: 0dad0b1e-659b-4ab8-80ca-d3b88ec3ee99
status: test
description: This rule identifies process executions of ProtocolHandler.exe where the command line contains URL schemes (ftp://, http://, or https://), indicating a file download attempt using the ProtocolHandler binary. Attackers can abuse signed Windows components to fetch external content while blending into normal system behavior. The detection relies on Windows process creation telemetry, matching the executable identity and the presence of these URL schemes in the command line.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1218/T1218.md
  - https://lolbas-project.github.io/lolbas/OtherMSBinaries/ProtocolHandler/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_protocolhandler_download.yml
author: frack113, Huntrule Team
date: 2021-07-13
modified: 2023-11-09
tags:
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \protocolhandler.exe
    - OriginalFileName: ProtocolHandler.exe
  selection_cli:
    CommandLine|contains:
      - ftp://
      - http://
      - https://
  condition: all of selection_*
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 104cdb48-a7a8-4ca7-a453-32942c6e5dcb
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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