Firefox describes their malware posture at https://support.mozilla.org/en-US/kb/how-does-phishing-and-malware-protection-work which heavily leverages Google SafeBrowsing, as do many a browser. Settings for SafeBrowsing are set in the browser.safebrowsing.downloads.remote.enabled pref. To lock this pref, you would need to create an autoconfig.js file in /Applications/Firefox.app/Contents/Resources/defaults/pref that points to a firefox.cfg file with a lock pref in it. To do so, create the autoconfig.js file and paste in these settings: // Configure SafeBrowsing pref("general.config.filename", "firefox.cfg"); pref("general.config.obscure_value", 0); Then create the firefox.cfg file and paste in these settings: // Configuring SafeBrowsing lockPref("browser.safebrowsing.downloads.remote.enabled", TRUE) Live Firefox preferences can be seen at /Users/charles.edge 1/Library/Application Support/Firefox/Profiles/*.default. Because SafeBrowsing is enabled by default, you shouldn’t see it listed unless it’s been disabled. But you can confirm it’s doing its…