Suspicious File Download From Browser Process Through Inline URL (via process_creation)

This rule detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension. This can be misused to download arbitrary files or to hide from the user for example by launching the browser in a minimized state.

SigmamediumWindowsv1
sigma
title: Suspicious File Download From Browser Process Through Inline URL (via process_creation)
id: 70faec69-d333-549a-a5a7-1cb2da56b4d4
status: stable
description: This rule detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension. This can be misused to download arbitrary files or to hide from the user for example by launching the browser in a minimized state.
references:
    - https://attack.mitre.org/techniques/T1105/
    - https://twitter.com/mrd0x/status/1478116126005641220
    - https://lolbas-project.github.io/lolbas/Binaries/Msedge/
author: Huntrule Team
date: 2026-06-12
tags:
    - attack.command-and-control
    - attack.t1105
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        Image|endswith:
            - '\brave.exe'
            - '\chrome.exe'
            - '\msedge.exe'
            - '\opera.exe'
            - '\vivaldi.exe'
    selection_http:
        CommandLine|contains: 'http'
    selection_extensions:
        - CommandLine|endswith:
              - '.7z'
              - '.dat'
              - '.dll'
              - '.exe'
              - '.hta'
              - '.ps1'
              - '.psm1'
              - '.txt'
              - '.vbe'
              - '.vbs'
              - '.zip'
        - CommandLine|contains:
              - '.7z"'
              - '.dat"'
              - '.dll"'
              - '.hta"'
              - '.ps1"'
              - '.psm1"'
              - '.txt"'
              - '.vbe"'
              - '.vbs"'
              - '.zip"'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_browsers_inline_file_download/info.yml

Known false positives

  • Unknown

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