Windows Browser Launched with Remote Debugging Flags

Alerts on Windows launches of Chromium-based browsers or Firefox with remote debugging command-line flags.

FreeReviewedSigma · Medium · v2
Product
windows
Category
process_creation
Author
pH-T (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-07-27
Updated
2026-07-31
title: Windows Browser Launched with Remote Debugging Flags
id: a3618bea-dafa-40a8-91d2-f173cb490e34
related:
  - id: 3e8207c5-fcd2-4ea6-9418-15d45b4890e4
    type: derived
  - id: b3d34dc5-2efd-4ae3-845f-8ec14921f449
    type: derived
status: test
description: This rule identifies when a Chromium-based browser is started with command-line arguments containing --remote-debugging-, or when Firefox is started with -start-debugger-server. Remote debugging enables an external control interface that attackers can abuse for browser manipulation and related injection workflows. It relies on Windows process creation telemetry, matching on the process command line (and Firefox image path suffix for that case).
references:
  - https://yoroi.company/wp-content/uploads/2022/05/EternityGroup_report_compressed.pdf
  - https://www.mdsec.co.uk/2022/10/analysing-lastpass-part-1/
  - https://github.com/defaultnamehere/cookie_crimes/
  - https://github.com/wunderwuzzi23/firefox-cookiemonster
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_browsers_remote_debugging.yml
author: pH-T (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-07-27
modified: 2022-12-23
tags:
  - attack.credential-access
  - attack.collection
  - attack.t1185
logsource:
  category: process_creation
  product: windows
detection:
  selection_chromium_based:
    CommandLine|contains: " --remote-debugging-"
  selection_firefox:
    Image|endswith: \firefox.exe
    CommandLine|contains: " -start-debugger-server"
  condition: 1 of selection_*
falsepositives:
  - Unknown
level: medium
license: DRL-1.1