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user.js
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1265 lines (1201 loc) · 78.1 KB
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/******
* name: arkenfox user.js
* date: 21 April 2026
* version: 144
* urls: https://github.com/arkenfox/user.js [repo]
* : https://arkenfox.github.io/gui/ [interactive]
* license: MIT: https://github.com/arkenfox/user.js/blob/master/LICENSE.txt
* README:
1. Consider using Tor Browser if it meets your needs or fits your threat model
* https://2019.www.torproject.org/about/torusers.html
2. Read the entire wiki
* https://github.com/arkenfox/user.js/wiki
3. If you skipped step 2, return to step 2
4. Make changes in a user-overrides.js
* There are often trade-offs and conflicts between security vs privacy vs anti-tracking
and these need to be balanced against functionality & convenience & breakage
* Some site breakage and unintended consequences will happen. Everyone's experience will differ
e.g. some user data is erased on exit (section 2800), change this to suit your needs
* While not 100% definitive, search for "[SETUP" tags
5. Some tag info
[SETUP-SECURITY] it's one item, read it
[SETUP-WEB] can cause some websites to break
[SETUP-CHROME] changes how Firefox itself behaves (i.e. not directly website related)
[SETUP-HARDEN] prefs you may like to add to overrides
6. Override Recipes: https://github.com/arkenfox/user.js/issues/1080
* RELEASES: https://github.com/arkenfox/user.js/releases
* Use the arkenfox release that matches your Firefox version
- DON'T wait for arkenfox to update Firefox, nothing major changes these days
* Each release
- run prefsCleaner to reset prefs made inactive, including deprecated (9999)
* ESR (Extended Support Release)
- It is recommended to not use the updater, or you will get a later version which may cause issues.
So you should manually append your overrides (and keep a copy), and manually update when you
change ESR releases (arkenfox is already past that release)
- If you decide to keep updating, then the onus is on you - also see section 9999
* INDEX:
0100: STARTUP
0200: GEOLOCATION
0300: QUIETER FOX
0400: SAFE BROWSING
0600: BLOCK IMPLICIT OUTBOUND
0700: DNS / DoH / PROXY / SOCKS
0800: LOCATION BAR / SEARCH BAR / SUGGESTIONS / HISTORY / FORMS
0900: PASSWORDS / PASSKEYS
1000: DISK AVOIDANCE
1200: HTTPS (SSL/TLS / OCSP / CERTS / HPKP)
1600: REFERERS
1700: CONTAINERS
2000: PLUGINS / MEDIA / WEBRTC
2400: DOM (DOCUMENT OBJECT MODEL)
2600: MISCELLANEOUS
2700: ETP (ENHANCED TRACKING PROTECTION)
2800: SHUTDOWN & SANITIZING
4000: FPP (fingerprintingProtection)
4500: OPTIONAL RFP (resistFingerprinting)
5000: OPTIONAL OPSEC
5500: OPTIONAL HARDENING
6000: DON'T TOUCH
7000: DON'T BOTHER
8000: DON'T BOTHER: FINGERPRINTING
8500: TELEMETRY
9000: NON-PROJECT RELATED
9999: DEPRECATED / RENAMED
******/
/* START: internal custom pref to test for syntax errors
* [NOTE] Not all syntax errors cause parsing to abort i.e. reaching the last debug pref
* no longer necessarily means that all prefs have been applied. Check the console right
* after startup for any warnings/error messages related to non-applied prefs
* [1] https://blog.mozilla.org/nnethercote/2018/03/09/a-new-preferences-parser-for-firefox/ ***/
user_pref("_user.js.parrot", "START: Oh yes, the Norwegian Blue... what's wrong with it?");
/* 0000: disable about:config warning ***/
user_pref("browser.aboutConfig.showWarning", false);
/*** [SECTION 0100]: STARTUP ***/
user_pref("_user.js.parrot", "0100 syntax error: the parrot's dead!");
/* 0102: set startup page [SETUP-CHROME]
* 0=blank, 1=home, 2=last visited page, 3=resume previous session
* [NOTE] Session Restore is cleared if history is also cleared (2811+), and not used in Private Browsing mode
* [SETTING] General>Startup>Restore previous session ***/
user_pref("browser.startup.page", 0);
/* 0103: set HOME+NEWWINDOW page
* about:home=Firefox Home (default, see 0105), custom URLs..., Blank Page
* [SETTING] Home>New Windows and Tabs>Homepage and new windows ***/
user_pref("browser.startup.homepage", "chrome://browser/content/blanktab.html");
/* 0104: set NEWTAB page
* true=Firefox Home (default, see 0105), false=blank page
* [SETTING] Home>New Windows and Tabs>New tabs ***/
user_pref("browser.newtabpage.enabled", false);
/* 0105: disable sponsored content on Firefox Home (Activity Stream)
* [SETTING] Home>Firefox Home Content ***/
user_pref("browser.newtabpage.activity-stream.showSponsored", false); // [FF58+] Sponsored stories
user_pref("browser.newtabpage.activity-stream.showSponsoredTopSites", false); // [FF83+] Sponsored shortcuts
user_pref("browser.newtabpage.activity-stream.showSponsoredCheckboxes", false); // [FF140+] Support Firefox
/* 0106: clear default topsites
* [NOTE] This does not block you from adding your own ***/
user_pref("browser.newtabpage.activity-stream.default.sites", "");
/*** [SECTION 0200]: GEOLOCATION ***/
user_pref("_user.js.parrot", "0200 syntax error: the parrot's definitely deceased!");
/* 0202: disable using the OS's geolocation service ***/
user_pref("geo.provider.ms-windows-location", false); // [WINDOWS]
user_pref("geo.provider.use_corelocation", false); // [MAC]
user_pref("geo.provider.use_geoclue", false); // [FF102+] [LINUX]
/*** [SECTION 0300]: QUIETER FOX ***/
user_pref("_user.js.parrot", "0300 syntax error: the parrot's not pinin' for the fjords!");
/** RECOMMENDATIONS ***/
/* 0320: disable recommendation pane in about:addons (uses Google Analytics) ***/
user_pref("extensions.getAddons.showPane", false); // [HIDDEN PREF]
/* 0321: disable recommendations in about:addons' Extensions and Themes panes [FF68+] ***/
user_pref("extensions.htmlaboutaddons.recommendations.enabled", false);
/* 0322: disable personalized Extension Recommendations in about:addons and AMO [FF65+]
* [NOTE] This pref has no effect when Health Reports (8501) are disabled
* [SETTING] Privacy & Security>Firefox Data Collection and Use>Allow personalized extension recommendations
* [1] https://support.mozilla.org/kb/personalized-extension-recommendations ***/
user_pref("browser.discovery.enabled", false);
/** ACTIVITY STREAM ***/
/* 0335: disable Firefox Home (Activity Stream) telemetry ***/
user_pref("browser.newtabpage.activity-stream.feeds.telemetry", false);
user_pref("browser.newtabpage.activity-stream.telemetry", false);
/** STUDIES ***/
/* 0340: disable Studies
* [SETTING] Privacy & Security>Firefox Data Collection and Use>Install and run studies ***/
user_pref("app.shield.optoutstudies.enabled", false);
/* 0341: disable Normandy/Shield [FF60+]
* Shield is a telemetry system that can push and test "recipes"
* [1] https://mozilla.github.io/normandy/ ***/
user_pref("app.normandy.enabled", false);
user_pref("app.normandy.api_url", "");
/** CRASH REPORTS ***/
/* 0350: disable Crash Reports ***/
user_pref("breakpad.reportURL", "");
user_pref("browser.tabs.crashReporting.sendReport", false); // [FF44+]
// user_pref("browser.crashReports.unsubmittedCheck.enabled", false); // [FF51+] [DEFAULT: false]
/* 0351: enforce no submission of backlogged Crash Reports [FF58+]
* [SETTING] Privacy & Security>Firefox Data Collection and Use>Send backlogged crash reports ***/
user_pref("browser.crashReports.unsubmittedCheck.autoSubmit2", false); // [DEFAULT: false]
/** OTHER ***/
/* 0360: disable Captive Portal detection
* [1] https://www.eff.org/deeplinks/2017/08/how-captive-portals-interfere-wireless-security-and-privacy ***/
user_pref("captivedetect.canonicalURL", "");
user_pref("network.captive-portal-service.enabled", false); // [FF52+]
/* 0361: disable Network Connectivity checks [FF65+]
* [1] https://bugzilla.mozilla.org/1460537 ***/
user_pref("network.connectivity-service.enabled", false);
/*** [SECTION 0400]: SAFE BROWSING (SB)
SB has taken many steps to preserve privacy. If required, a full url is never sent
to Google, only a part-hash of the prefix, hidden with noise of other real part-hashes.
Firefox takes measures such as stripping out identifying parameters and since SBv4 (FF57+)
doesn't even use cookies. (#Turn on browser.safebrowsing.debug to monitor this activity).
FF147+ uses SBv5 which incorporates Oblivous HTTP [5] and SBv5's local list mode [6]
[1] https://feeding.cloud.geek.nz/posts/how-safe-browsing-works-in-firefox/
[2] https://wiki.mozilla.org/Security/Safe_Browsing
[3] https://support.mozilla.org/kb/how-does-phishing-and-malware-protection-work
[4] https://educatedguesswork.org/posts/safe-browsing-privacy/
[5] https://developers.google.com/safe-browsing/reference
[6] https://developers.google.com/safe-browsing/reference/Local.List.Mode
***/
user_pref("_user.js.parrot", "0400 syntax error: the parrot's passed on!");
/* 0401: disable SB (Safe Browsing)
* [WARNING] Do this at your own risk! These are the master switches
* [SETTING] Privacy & Security>Security>... Block dangerous and deceptive content ***/
// user_pref("browser.safebrowsing.malware.enabled", false);
// user_pref("browser.safebrowsing.phishing.enabled", false);
/* 0402: disable SB checks for downloads (both local lookups + remote)
* This is the master switch for the safebrowsing.downloads* prefs (0403, 0404)
* [SETTING] Privacy & Security>Security>... "Block dangerous downloads" ***/
// user_pref("browser.safebrowsing.downloads.enabled", false);
/* 0403: disable SB checks for downloads (remote)
* To verify the safety of certain executable files, Firefox may submit some information about the
* file, including the name, origin, size and a cryptographic hash of the contents, to the Google
* Safe Browsing service which helps Firefox determine whether or not the file should be blocked
* [SETUP-SECURITY] If you do not understand this, or you want this protection, then override this ***/
user_pref("browser.safebrowsing.downloads.remote.enabled", false);
// user_pref("browser.safebrowsing.downloads.remote.url", ""); // Defense-in-depth
/* 0404: disable SB checks for unwanted software
* [SETTING] Privacy & Security>Security>... "Warn you about unwanted and uncommon software" ***/
// user_pref("browser.safebrowsing.downloads.remote.block_potentially_unwanted", false);
// user_pref("browser.safebrowsing.downloads.remote.block_uncommon", false);
/* 0405: disable "ignore this warning" on SB warnings [FF45+]
* If clicked, it bypasses the block for that session. This is a means for admins to enforce SB
* [TEST] see https://github.com/arkenfox/user.js/wiki/Appendix-A-Test-Sites#-mozilla
* [1] https://bugzilla.mozilla.org/1226490 ***/
// user_pref("browser.safebrowsing.allowOverride", false);
/*** [SECTION 0600]: BLOCK IMPLICIT OUTBOUND [not explicitly asked for - e.g. clicked on] ***/
user_pref("_user.js.parrot", "0600 syntax error: the parrot's no more!");
/* 0601: disable link prefetching
* [1] https://developer.mozilla.org/docs/Web/HTTP/Link_prefetching_FAQ ***/
user_pref("network.prefetch-next", false);
/* 0602: disable DNS prefetching
* [1] https://developer.mozilla.org/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control ***/
user_pref("network.dns.disablePrefetch", true);
user_pref("network.dns.disablePrefetchFromHTTPS", true);
/* 0604: disable link-mouseover opening connection to linked server
* [1] https://news.slashdot.org/story/15/08/14/2321202/how-to-quash-firefoxs-silent-requests ***/
user_pref("network.http.speculative-parallel-limit", 0);
/* 0605: disable mousedown speculative connections on bookmarks and history [FF98+] ***/
user_pref("browser.places.speculativeConnect.enabled", false);
/* 0610: enforce no "Hyperlink Auditing" (click tracking)
* [1] https://www.bleepingcomputer.com/news/software/major-browsers-to-prevent-disabling-of-click-tracking-privacy-risk/ ***/
// user_pref("browser.send_pings", false); // [DEFAULT: false]
/*** [SECTION 0700]: DNS / DoH / PROXY / SOCKS ***/
user_pref("_user.js.parrot", "0700 syntax error: the parrot's given up the ghost!");
/* 0702: set the proxy server to do any DNS lookups when using SOCKS
* e.g. in Tor, this stops your local DNS server from knowing your Tor destination
* as a remote Tor node will handle the DNS request
* [1] https://trac.torproject.org/projects/tor/wiki/doc/TorifyHOWTO/WebBrowsers ***/
user_pref("network.proxy.socks_remote_dns", true);
/* 0703: disable using UNC (Uniform Naming Convention) paths [FF61+]
* [SETUP-CHROME] Can break extensions for profiles on network shares
* [1] https://bugzilla.mozilla.org/1413868 ***/
user_pref("network.file.disable_unc_paths", true); // [HIDDEN PREF]
/* 0704: disable GIO as a potential proxy bypass vector
* Gvfs/GIO has a set of supported protocols like obex, network, archive, computer,
* dav, cdda, gphoto2, trash, etc. From FF87-117, by default only sftp was accepted
* [1] https://bugzilla.mozilla.org/1433507
* [2] https://en.wikipedia.org/wiki/GVfs
* [3] https://en.wikipedia.org/wiki/GIO_(software) ***/
user_pref("network.gio.supported-protocols", ""); // [HIDDEN PREF] [DEFAULT: ""]
/* 0705: disable proxy direct failover for system requests [FF91+]
* [WARNING] Default true is a security feature against malicious extensions [1]
* [SETUP-CHROME] If you use a proxy and you trust your extensions
* [1] https://blog.mozilla.org/security/2021/10/25/securing-the-proxy-api-for-firefox-add-ons/ ***/
// user_pref("network.proxy.failover_direct", false);
/* 0706: disable proxy bypass for system request failures [FF95+]
* RemoteSettings, UpdateService, Telemetry [1]
* [WARNING] If false, this will break the fallback for some security features
* [SETUP-CHROME] If you use a proxy and you understand the security impact
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1732792,1733994,1733481 ***/
// user_pref("network.proxy.allow_bypass", false);
/* 0710: enable DNS-over-HTTPS (DoH) [FF60+]
* 0=default, 2=increased (TRR (Trusted Recursive Resolver) first), 3=max (TRR only), 5=off (no rollout)
* see "doh-rollout.home-region": USA 2019, Canada 2021, Russia/Ukraine 2022 [3]
* [SETTING] Privacy & Security>DNS over HTTPS
* [1] https://hacks.mozilla.org/2018/05/a-cartoon-intro-to-dns-over-https/
* [2] https://wiki.mozilla.org/Security/DOH-resolver-policy
* [3] https://support.mozilla.org/kb/firefox-dns-over-https
* [4] https://www.eff.org/deeplinks/2020/12/dns-doh-and-odoh-oh-my-year-review-2020 ***/
// user_pref("network.trr.mode", 3);
/* 0712: set DoH provider
* The custom uri is the value shown when you "Choose provider>Custom>"
* [NOTE] If you USE custom then "network.trr.uri" should be set the same
* [SETTING] Privacy & Security>DNS over HTTPS>Increased/Max>Choose provider ***/
// user_pref("network.trr.uri", "https://example.dns");
// user_pref("network.trr.custom_uri", "https://example.dns");
/*** [SECTION 0800]: LOCATION BAR / SEARCH BAR / SUGGESTIONS / HISTORY / FORMS ***/
user_pref("_user.js.parrot", "0800 syntax error: the parrot's ceased to be!");
/* 0801: disable location bar making speculative connections [FF56+]
* [1] https://bugzilla.mozilla.org/1348275 ***/
user_pref("browser.urlbar.speculativeConnect.enabled", false);
/* 0802: disable location bar contextual suggestions
* [NOTE] The UI is controlled by the .enabled pref
* [SETTING] Search>Address Bar>Suggestions from...
* [1] https://blog.mozilla.org/data/2021/09/15/data-and-firefox-suggest/ ***/
user_pref("browser.urlbar.quicksuggest.enabled", false); // [FF92+]
user_pref("browser.urlbar.suggest.quicksuggest.nonsponsored", false); // [FF95+]
user_pref("browser.urlbar.suggest.quicksuggest.sponsored", false); // [FF92+]
/* 0803: disable live search suggestions
* [NOTE] Both must be true for live search to work in the location bar
* [SETUP-CHROME] Override these if you trust and use a privacy respecting search engine
* [SETTING] Search>Show search suggestions | Show search suggestions in address bar results ***/
user_pref("browser.search.suggest.enabled", false);
user_pref("browser.urlbar.suggest.searches", false);
/* 0805: disable urlbar trending search suggestions [FF118+]
* [SETTING] Search>Search Suggestions>Show trending search suggestions (FF119) ***/
user_pref("browser.urlbar.trending.featureGate", false);
/* 0806: disable urlbar suggestions ***/
user_pref("browser.urlbar.addons.featureGate", false); // [FF115+]
user_pref("browser.urlbar.amp.featureGate", false); // [FF141+] adMarketplace
user_pref("browser.urlbar.importantDates.featureGate", false); // [FF143+]
user_pref("browser.urlbar.market.featureGate", false); // [FF143+] stock market
user_pref("browser.urlbar.mdn.featureGate", false); // [FF117+]
user_pref("browser.urlbar.weather.featureGate", false); // [FF108+]
user_pref("browser.urlbar.wikipedia.featureGate", false); // [FF141+]
user_pref("browser.urlbar.yelp.featureGate", false); // [FF124+]
user_pref("browser.urlbar.yelpRealtime.featureGate", false); // [FF144+]
/* 0807: disable urlbar clipboard suggestions [FF118+] ***/
// user_pref("browser.urlbar.clipboard.featureGate", false);
/* 0808: disable recent searches [FF120+]
* [NOTE] Recent searches are cleared if history is cleared (2811+)
* [1] https://support.mozilla.org/kb/search-suggestions-firefox ***/
// user_pref("browser.urlbar.recentsearches.featureGate", false);
/* 0810: disable search and form history
* [NOTE] We also clear formdata on exit (2811+)
* [SETUP-WEB] Be aware that autocomplete form data can be read by third parties [1][2]
* [SETTING] Privacy & Security>History>Custom Settings>Remember search and form history
* [1] https://blog.mindedsecurity.com/2011/10/autocompleteagain.html
* [2] https://bugzilla.mozilla.org/381681 ***/
user_pref("browser.formfill.enable", false);
/* 0815: disable tab-to-search [FF85+]
* Alternatively, you can exclude on a per-engine basis by unchecking them in Options>Search
* [SETTING] Search>Address Bar>When using the address bar, suggest>Search engines ***/
// user_pref("browser.urlbar.suggest.engines", false);
/* 0820: disable coloring of visited links
* [SETUP-HARDEN] Bulk rapid history sniffing was mitigated in 2010 [1][2]. Slower and more expensive
* redraw timing attacks were largely mitigated in FF77+ [3]. Using RFP (4501) further hampers timing
* attacks. History can also be cleared on exit (2811+). However, social engineering [2#limits][4][5]
* and advanced targeted timing attacks could still produce usable results
* [1] https://developer.mozilla.org/docs/Web/CSS/Privacy_and_the_:visited_selector
* [2] https://dbaron.org/mozilla/visited-privacy
* [3] https://bugzilla.mozilla.org/1632765
* [4] https://earthlng.github.io/testpages/visited_links.html (see github wiki APPENDIX A on how to use)
* [5] https://lcamtuf.blogspot.com/2016/08/css-mix-blend-mode-is-bad-for-keeping.html ***/
// user_pref("layout.css.visited_links_enabled", false);
/* 0830: enable separate default search engine in Private Windows and its UI setting
* [SETTING] Search>Default Search Engine>Choose a different default search engine for Private Windows only ***/
user_pref("browser.search.separatePrivateDefault", true); // [FF70+]
user_pref("browser.search.separatePrivateDefault.ui.enabled", true); // [FF71+]
/*** [SECTION 0900]: PASSWORDS / PASSKEYS
[1] https://support.mozilla.org/kb/use-primary-password-protect-stored-logins-and-pas
***/
user_pref("_user.js.parrot", "0900 syntax error: the parrot's expired!");
/* 0903: disable auto-filling username & password form fields
* can leak in cross-site forms *and* be spoofed
* [NOTE] Username & password is still available when you enter the field
* [SETTING] Privacy & Security>Passwords>Autofill logins and passwords
* [1] https://freedom-to-tinker.com/2017/12/27/no-boundaries-for-user-identities-web-trackers-exploit-browser-login-managers/
* [2] https://homes.esat.kuleuven.be/~asenol/leaky-forms/ ***/
user_pref("signon.autofillForms", false);
/* 0904: disable formless login capture for Password Manager [FF51+] ***/
user_pref("signon.formlessCapture.enabled", false);
/* 0905: limit (or disable) HTTP authentication credentials dialogs triggered by sub-resources [FF41+]
* hardens against potential credentials phishing
* 0 = don't allow sub-resources to open HTTP authentication credentials dialogs
* 1 = don't allow cross-origin sub-resources to open HTTP authentication credentials dialogs
* 2 = allow sub-resources to open HTTP authentication credentials dialogs (default) ***/
user_pref("network.auth.subresource-http-auth-allow", 1);
/* 0906: enforce no automatic authentication on Microsoft sites [FF91+] [WINDOWS 10+]
* [SETTING] Privacy & Security>Logins and Passwords>Allow Windows single sign-on for...
* [1] https://support.mozilla.org/kb/windows-sso ***/
// user_pref("network.http.windows-sso.enabled", false); // [DEFAULT: false]
/* 0907: enforce no automatic authentication on Microsoft sites [FF131+] [MAC]
* On macOS, SSO only works on corporate devices ***/
// user_pref("network.http.microsoft-entra-sso.enabled", false); // [DEFAULT: false]
/* 0910: enforce no direct attestation in passkeys [FF144+]
// [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1981587 ***/
user_pref("security.webauthn.always_allow_direct_attestation", false); // [DEFAULT: false]
/*** [SECTION 1000]: DISK AVOIDANCE ***/
user_pref("_user.js.parrot", "1000 syntax error: the parrot's gone to meet 'is maker!");
/* 1001: disable disk cache
* [NOTE] We also clear cache on exit (2811+)
* [SETUP-CHROME] If you think disk cache helps perf, then feel free to override this ***/
user_pref("browser.cache.disk.enable", false);
/* 1002: set media cache in Private Browsing to in-memory and increase its maximum size
* [NOTE] MSE (Media Source Extensions) are already stored in-memory in PB ***/
user_pref("browser.privatebrowsing.forceMediaMemoryCache", true); // [FF75+]
user_pref("media.memory_cache_max_size", 65536);
/* 1003: disable storing extra session data [SETUP-CHROME]
* define on which sites to save extra session data such as form content, cookies and POST data
* 0=everywhere, 1=unencrypted sites, 2=nowhere ***/
user_pref("browser.sessionstore.privacy_level", 2);
/* 1005: disable automatic Firefox start and session restore after reboot [FF62+] [WINDOWS]
* [1] https://bugzilla.mozilla.org/603903 ***/
user_pref("toolkit.winRegisterApplicationRestart", false);
/* 1006: disable favicons in shortcuts [WINDOWS]
* URL shortcuts use a cached randomly named .ico file which is stored in your
* profile/shortcutCache directory. The .ico remains after the shortcut is deleted
* If set to false then the shortcuts use a generic Firefox icon ***/
user_pref("browser.shell.shortcutFavicons", false);
/*** [SECTION 1200]: HTTPS (SSL/TLS / OCSP / CERTS / HPKP)
Your cipher and other settings can be used in server side fingerprinting
[TEST] https://www.ssllabs.com/ssltest/viewMyClient.html
[TEST] https://browserleaks.com/ssl
[TEST] https://ja3er.com/
[1] https://www.securityartwork.es/2017/02/02/tls-client-fingerprinting-with-bro/
***/
user_pref("_user.js.parrot", "1200 syntax error: the parrot's a stiff!");
/** SSL (Secure Sockets Layer) / TLS (Transport Layer Security) ***/
/* 1201: require safe negotiation
* Blocks connections to servers that don't support RFC 5746 [2] as they're potentially vulnerable to a
* MiTM attack [3]. A server without RFC 5746 can be safe from the attack if it disables renegotiations
* but the problem is that the browser can't know that. Setting this pref to true is the only way for the
* browser to ensure there will be no unsafe renegotiations on the channel between the browser and the server
* [SETUP-WEB] SSL_ERROR_UNSAFE_NEGOTIATION: is it worth overriding this for that one site?
* [STATS] SSL Labs (Nov 2025) reports almost 99.85% of top sites have secure renegotiation [4]
* [1] https://wiki.mozilla.org/Security:Renegotiation
* [2] https://datatracker.ietf.org/doc/html/rfc5746
* [3] https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3555
* [4] https://www.ssllabs.com/ssl-pulse/ ***/
user_pref("security.ssl.require_safe_negotiation", true);
/* 1206: disable TLS1.3 0-RTT (round-trip time) [FF51+]
* This data is not forward secret, as it is encrypted solely under keys derived using
* the offered PSK. There are no guarantees of non-replay between connections
* [1] https://github.com/tlswg/tls13-spec/issues/1001
* [2] https://www.rfc-editor.org/rfc/rfc9001.html#name-replay-attacks-with-0-rtt
* [3] https://blog.cloudflare.com/tls-1-3-overview-and-q-and-a/ ***/
user_pref("security.tls.enable_0rtt_data", false);
/** CERTS / HPKP (HTTP Public Key Pinning) ***/
/* 1223: enable strict PKP (Public Key Pinning)
* 0=disabled, 1=allow user MiTM (default; such as your antivirus), 2=strict
* [SETUP-WEB] MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE ***/
user_pref("security.cert_pinning.enforcement_level", 2);
/* 1224: enable CRLite [FF73+]
* 0 = disabled
* 1 = consult CRLite but only collect telemetry
* 2 = consult CRLite and enforce both "Revoked" and "Not Revoked" results (default)
* 3 = consult CRLite and enforce "Not Revoked" results, but defer to OCSP for "Revoked" (removed FF145)
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1429800,1670985,1753071
* [2] https://blog.mozilla.org/security/tag/crlite/
* [3] https://hacks.mozilla.org/2025/08/crlite-fast-private-and-comprehensive-certificate-revocation-checking-in-firefox/ ***/
user_pref("security.remote_settings.crlite_filters.enabled", true); // [DEFAULT: true]
user_pref("security.pki.crlite_mode", 2); // [DEFAULT: 2 FF142+]
/** MIXED CONTENT ***/
/* 1241: disable insecure passive content (such as images) on https pages ***/
// user_pref("security.mixed_content.block_display_content", true); // Defense-in-depth (see 1244)
/* 1244: enable HTTPS-Only mode in all windows
* When the top-level is HTTPS, insecure subresources are also upgraded (silent fail)
* [SETTING] to add site exceptions: Padlock>HTTPS-Only mode>On (after "Continue to HTTP Site")
* [SETTING] Privacy & Security>HTTPS-Only Mode (and manage exceptions)
* [TEST] http://example.com [upgrade]
* [TEST] http://httpforever.com/ | http://http.rip [no upgrade] ***/
user_pref("dom.security.https_only_mode", true); // [FF76+]
// user_pref("dom.security.https_only_mode_pbm", true); // [FF80+]
/* 1245: enable HTTPS-Only mode for local resources [FF77+] ***/
// user_pref("dom.security.https_only_mode.upgrade_local", true);
/* 1246: disable HTTP background requests [FF82+]
* When attempting to upgrade, if the server doesn't respond within 3 seconds, Firefox sends
* a top-level HTTP request without path in order to check if the server supports HTTPS or not
* This is done to avoid waiting for a timeout which takes 90 seconds
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1642387,1660945 ***/
user_pref("dom.security.https_only_mode_send_http_background_request", false);
/** UI (User Interface) ***/
/* 1270: display warning on the padlock for "broken security" (if 1201 is false)
* Bug: warning padlock not indicated for subresources on a secure page! [2]
* [1] https://wiki.mozilla.org/Security:Renegotiation
* [2] https://bugzilla.mozilla.org/1353705 ***/
user_pref("security.ssl.treat_unsafe_negotiation_as_broken", true);
/* 1272: display advanced information on Insecure Connection warning pages
* only works when it's possible to add an exception
* i.e. it doesn't work for HSTS discrepancies (https://subdomain.preloaded-hsts.badssl.com/)
* [TEST] https://expired.badssl.com/ ***/
user_pref("browser.xul.error_pages.expert_bad_cert", true);
/*** [SECTION 1600]: REFERERS
full URI: https://example.com:8888/foo/bar.html?id=1234
scheme+host+port+path: https://example.com:8888/foo/bar.html
scheme+host+port: https://example.com:8888
[1] https://feeding.cloud.geek.nz/posts/tweaking-referrer-for-privacy-in-firefox/
***/
user_pref("_user.js.parrot", "1600 syntax error: the parrot rests in peace!");
/* 1602: control the amount of cross-origin information to send [FF52+]
* 0=send full URI (default), 1=scheme+host+port+path, 2=scheme+host+port ***/
user_pref("network.http.referer.XOriginTrimmingPolicy", 2);
/*** [SECTION 1700]: CONTAINERS ***/
user_pref("_user.js.parrot", "1700 syntax error: the parrot's bit the dust!");
/* 1701: enable Container Tabs and its UI setting [FF50+]
* [SETTING] General>Tabs>Enable Container Tabs
* https://wiki.mozilla.org/Security/Contextual_Identity_Project/Containers ***/
user_pref("privacy.userContext.enabled", true);
user_pref("privacy.userContext.ui.enabled", true);
/* 1702: set behavior on "+ Tab" button to display container menu on left click [FF74+]
* [NOTE] The menu is always shown on long press and right click
* [SETTING] General>Tabs>Enable Container Tabs>Settings>Select a container for each new tab ***/
// user_pref("privacy.userContext.newTabContainerOnLeftClick.enabled", true);
/* 1703: set external links to open in site-specific containers [FF123+]
* [SETUP-WEB] Depending on your container extension(s) and their settings
* true=Firefox will not choose a container (so your extension can)
* false=Firefox will choose the container/no-container (default)
* [1] https://bugzilla.mozilla.org/1874599 ***/
// user_pref("browser.link.force_default_user_context_id_for_external_opens", true);
/*** [SECTION 2000]: PLUGINS / MEDIA / WEBRTC ***/
user_pref("_user.js.parrot", "2000 syntax error: the parrot's snuffed it!");
/* 2002: force WebRTC inside the proxy [FF70+] ***/
user_pref("media.peerconnection.ice.proxy_only_if_behind_proxy", true);
/* 2003: force a single network interface for ICE candidates generation [FF42+]
* When using a system-wide proxy, it uses the proxy interface
* [1] https://developer.mozilla.org/docs/Web/API/RTCIceCandidate
* [2] https://wiki.mozilla.org/Media/WebRTC/Privacy ***/
user_pref("media.peerconnection.ice.default_address_only", true);
/* 2004: force exclusion of private IPs from ICE candidates [FF51+]
* [SETUP-HARDEN] This will protect your private IP even in TRUSTED scenarios after you
* grant device access, but often results in breakage on video-conferencing platforms ***/
// user_pref("media.peerconnection.ice.no_host", true);
/* 2020: disable GMP (Gecko Media Plugins)
* [1] https://wiki.mozilla.org/GeckoMediaPlugins ***/
// user_pref("media.gmp-provider.enabled", false);
/*** [SECTION 2400]: DOM (DOCUMENT OBJECT MODEL) ***/
user_pref("_user.js.parrot", "2400 syntax error: the parrot's kicked the bucket!");
/* 2402: prevent scripts from moving and resizing open windows ***/
user_pref("dom.disable_window_move_resize", true);
/*** [SECTION 2600]: MISCELLANEOUS ***/
user_pref("_user.js.parrot", "2600 syntax error: the parrot's run down the curtain!");
/* 2603: remove temp files opened from non-PB windows with an external application
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=302433,1738574 ***/
user_pref("browser.download.start_downloads_in_tmp_dir", true); // [FF102+]
user_pref("browser.helperApps.deleteTempFileOnExit", true);
/* 2606: disable UITour backend so there is no chance that a remote page can use it ***/
user_pref("browser.uitour.enabled", false);
// user_pref("browser.uitour.url", ""); // Defense-in-depth
/* 2608: reset remote debugging to disabled
* [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/16222 ***/
user_pref("devtools.debugger.remote-enabled", false); // [DEFAULT: false]
/* 2615: disable websites overriding Firefox's keyboard shortcuts [FF58+]
* 0 (default) or 1=allow, 2=block
* [SETTING] to add site exceptions: Ctrl+I>Permissions>Override Keyboard Shortcuts ***/
// user_pref("permissions.default.shortcuts", 2);
/* 2616: remove special permissions for certain mozilla domains [FF35+]
* [1] resource://app/defaults/permissions ***/
user_pref("permissions.manager.defaultsUrl", "");
/* 2619: use Punycode in Internationalized Domain Names to eliminate possible spoofing
* [SETUP-WEB] Might be undesirable for non-latin alphabet users since legitimate IDN's are also punycoded
* [TEST] https://www.xn--80ak6aa92e.com/ (www.apple.com)
* [1] https://wiki.mozilla.org/IDN_Display_Algorithm
* [2] https://en.wikipedia.org/wiki/IDN_homograph_attack
* [3] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=punycode+firefox
* [4] https://www.xudongz.com/blog/2017/idn-phishing/ ***/
user_pref("network.IDN_show_punycode", true);
/* 2620: enforce PDFJS, disable PDFJS scripting
* This setting controls if the option "Display in Firefox" is available in the setting below
* and by effect controls whether PDFs are handled in-browser or externally ("Ask" or "Open With")
* [WHY] pdfjs is lightweight, open source, and secure: In the last 10 years it has only had
* two known exploits, both in 2024: one 'Severe' and one 'Important' [1]
* It doesn't break "state separation" of browser content (by not sharing with OS, independent apps).
* It maintains disk avoidance and application data isolation. It's convenient. You can still save to disk.
* [NOTE] JS can still force a pdf to open in-browser by bundling its own code
* [SETUP-CHROME] You may prefer a different pdf reader for security/workflow reasons
* [SETTING] General>Applications>Portable Document Format (PDF)
* [1] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=pdf.js+firefox ***/
user_pref("pdfjs.disabled", false); // [DEFAULT: false]
user_pref("pdfjs.enableScripting", false); // [FF86+]
/* 2624: disable middle click on new tab button opening URLs or searches using clipboard [FF115+] ***/
user_pref("browser.tabs.searchclipboardfor.middleclick", false); // [DEFAULT: false NON-LINUX]
/* 2630: disable content analysis by DLP (Data Loss Prevention) agents
* DLP agents are background processes on managed computers that allow enterprises to monitor locally running
* applications for data exfiltration events, which they can allow/block based on customer defined DLP policies.
* 0=Block all requests, 1=Warn on all requests (which lets the user decide), 2=Allow all requests
* [1] https://github.com/chromium/content_analysis_sdk ***/
user_pref("browser.contentanalysis.enabled", false); // [FF121+] [DEFAULT: false]
user_pref("browser.contentanalysis.default_result", 0); // [FF127+] [DEFAULT: 0]
/* 2635: disable referrer and storage access for resources injected by content scripts [FF139+] ***/
user_pref("privacy.antitracking.isolateContentScriptResources", true);
/* 2640: disable CSP Level 2 Reporting [FF140+] ***/
user_pref("security.csp.reporting.enabled", false);
/** DOWNLOADS ***/
/* 2651: enable user interaction for security by always asking where to download
* [SETUP-CHROME] On Android this blocks longtapping and saving images
* [SETTING] General>Downloads>Always ask you where to save files ***/
user_pref("browser.download.useDownloadDir", false);
/* 2652: disable downloads panel opening on every download [FF96+] ***/
user_pref("browser.download.alwaysOpenPanel", false);
/* 2653: disable adding downloads to the system's "recent documents" list ***/
user_pref("browser.download.manager.addToRecentDocs", false);
/* 2654: enable user interaction for security by always asking how to handle new mimetypes [FF101+]
* [SETTING] General>Files and Applications>What should Firefox do with other files ***/
user_pref("browser.download.always_ask_before_handling_new_types", true);
/** EXTENSIONS ***/
/* 2660: limit allowed extension directories
* 1=profile, 2=user, 4=application, 8=system, 16=temporary, 31=all
* The pref value represents the sum: e.g. 5 would be profile and application directories
* [SETUP-CHROME] Breaks usage of files which are installed outside allowed directories
* [1] https://archive.is/DYjAM ***/
user_pref("extensions.enabledScopes", 5); // [HIDDEN PREF]
// user_pref("extensions.autoDisableScopes", 15); // [DEFAULT: 15]
/* 2661: disable bypassing 3rd party extension install prompts [FF82+]
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1659530,1681331 ***/
user_pref("extensions.postDownloadThirdPartyPrompt", false);
/* 2662: disable webextension restrictions on certain mozilla domains (you also need 4503) [FF60+]
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1384330,1406795,1415644,1453988 ***/
// user_pref("extensions.webextensions.restrictedDomains", "");
/*** [SECTION 2700]: ETP (ENHANCED TRACKING PROTECTION) ***/
user_pref("_user.js.parrot", "2700 syntax error: the parrot's joined the bleedin' choir invisible!");
/* 2701: enable ETP Strict Mode [FF86+]
* ETP Strict Mode enables Total Cookie Protection (TCP)
* [NOTE] Adding site exceptions disables all ETP protections for that site and increases the risk of
* cross-site state tracking e.g. exceptions for SiteA and SiteB means PartyC on both sites is shared
* [1] https://blog.mozilla.org/security/2021/02/23/total-cookie-protection/
* [SETTING] to add site exceptions: Urlbar>ETP Shield
* [SETTING] to manage site exceptions: Options>Privacy & Security>Enhanced Tracking Protection>Manage Exceptions ***/
user_pref("browser.contentblocking.category", "strict"); // [HIDDEN PREF]
/* 2702: disable ETP web compat features (about:compat) [FF93+]
* [SETUP-HARDEN] Includes skip lists, heuristics (SmartBlock) and automatic grants
* Opener and redirect heuristics are granted for 30 days, see [3]
* [1] https://blog.mozilla.org/security/2021/07/13/smartblock-v2/
* [2] https://hg.mozilla.org/mozilla-central/rev/e5483fd469ab#l4.12
* [3] https://developer.mozilla.org/docs/Web/Privacy/State_Partitioning#storage_access_heuristics ***/
// user_pref("privacy.antitracking.enableWebcompat", false);
/* 2705: set ETP Strict/Custom exception lists (FF141+)
[SETTING] Options>Privacy & Security>Enhanced Tracking Protection>Strict/Custom>Fix major [baseline] | minor [convenience]
[1] https://support.mozilla.org/en-US/kb/manage-enhanced-tracking-protection-exceptions
[2] https://etp-exceptions.mozilla.org/ ***/
user_pref("privacy.trackingprotection.allow_list.baseline.enabled", true); // [DEFAULT: true]
user_pref("privacy.trackingprotection.allow_list.convenience.enabled", true); // [DEFAULT: true]
/*** [SECTION 2800]: SHUTDOWN & SANITIZING
We enable sanitizeOnShutdown to help prevent 1st party website tracking across sessions.
We consider history/downloads, which are not accessible to websites, as orthogonal and exempt these
[SETUP-HARDEN] to clear all history/downloads on close, add the appropriate overrides from 2800's
***/
user_pref("_user.js.parrot", "2800 syntax error: the parrot's bleedin' demised!");
/* 2810: enable Firefox to clear items on shutdown
* [NOTE] In FF129+ clearing "siteSettings" on shutdown (2811+), or manually via site data (2820+) and
* via history (2830), will no longer remove sanitize on shutdown "cookie and site data" site exceptions (2815)
* [SETTING] Privacy & Security>History>Custom Settings>Clear history when Firefox closes | Settings ***/
user_pref("privacy.sanitize.sanitizeOnShutdown", true);
/** SANITIZE ON SHUTDOWN: IGNORES "ALLOW" SITE EXCEPTIONS ***/
/* 2811: set/enforce clearOnShutdown items (if 2810 is true) [SETUP-CHROME] [FF128+] ***/
user_pref("privacy.clearOnShutdown_v2.cache", true); // [DEFAULT: true]
user_pref("privacy.clearOnShutdown_v2.historyFormDataAndDownloads", false); // [DEFAULT: true]
// user_pref("privacy.clearOnShutdown_v2.siteSettings", false); // [DEFAULT: false]
/* 2812: set/enforce clearOnShutdown items [FF136+] ***/
user_pref("privacy.clearOnShutdown_v2.browsingHistoryAndDownloads", false); // [DEFAULT: true]
user_pref("privacy.clearOnShutdown_v2.downloads", false); // [HIDDEN]
user_pref("privacy.clearOnShutdown_v2.formdata", true);
/* 2813: set Session Restore to clear on shutdown (if 2810 is true) [FF34+]
* [NOTE] Not needed if Session Restore is not used (0102) or it is already cleared with history (2811+)
* [NOTE] If true, this prevents resuming from crashes (also see 5008) ***/
// user_pref("privacy.clearOnShutdown.openWindows", true);
/** SANITIZE ON SHUTDOWN: RESPECTS "ALLOW" SITE EXCEPTIONS ***/
/* 2815: set "Cookies" and "Site Data" to clear on shutdown (if 2810 is true) [SETUP-CHROME] [FF128+]
* [NOTE] Exceptions: For cross-domain logins, add exceptions for both sites
* e.g. https://www.youtube.com (site) + https://accounts.google.com (single sign on)
* [WARNING] Be selective with what sites you "Allow", as they also disable partitioning (1767271)
* [SETTING] to add site exceptions: Ctrl+I>Permissions>Cookies>Allow (when on the website in question)
* [SETTING] to manage site exceptions: Options>Privacy & Security>Permissions>Settings ***/
user_pref("privacy.clearOnShutdown_v2.cookiesAndStorage", true);
/** SANITIZE SITE DATA: IGNORES "ALLOW" SITE EXCEPTIONS ***/
/* 2820: set manual "Clear Data" items [SETUP-CHROME] [FF128+]
* Firefox remembers your last choices. This will reset them when you start Firefox
* [SETTING] Privacy & Security>Browser Privacy>Cookies and Site Data>Clear Data ***/
user_pref("privacy.clearSiteData.cache", true); // [DEFAULT: true]
user_pref("privacy.clearSiteData.cookiesAndStorage", false); // keep false until it respects "allow" site exceptions
user_pref("privacy.clearSiteData.historyFormDataAndDownloads", false);
// user_pref("privacy.clearSiteData.siteSettings", false);
/* 2821: set manual "Clear Data" items [FF136+] ***/
user_pref("privacy.clearSiteData.browsingHistoryAndDownloads", false);
user_pref("privacy.clearSiteData.formdata", true);
/** SANITIZE HISTORY: IGNORES "ALLOW" SITE EXCEPTIONS ***/
/* 2830: set manual "Clear History" items, also via Ctrl-Shift-Del [SETUP-CHROME] [FF128+]
* Firefox remembers your last choices. This will reset them when you start Firefox
* [SETTING] Privacy & Security>History>Custom Settings>Clear History ***/
user_pref("privacy.clearHistory.cache", true); // [DEFAULT: true]
user_pref("privacy.clearHistory.cookiesAndStorage", false);
user_pref("privacy.clearHistory.historyFormDataAndDownloads", false); // [DEFAULT: true]
// user_pref("privacy.clearHistory.siteSettings", false); // [DEFAULT: false]
/* 2831: set manual "Clear History" items [FF136+] ***/
user_pref("privacy.clearHistory.browsingHistoryAndDownloads", false); // [DEFAULT: true]
user_pref("privacy.clearHistory.formdata", true);
/** SANITIZE MANUAL: TIMERANGE ***/
/* 2840: set "Time range to clear" for "Clear Data" (2820+) and "Clear History" (2830+)
* Firefox remembers your last choice. This will reset the value when you start Firefox
* 0=everything, 1=last hour, 2=last two hours, 3=last four hours, 4=today
* [NOTE] Values 5 (last 5 minutes) and 6 (last 24 hours) are not listed in the dropdown,
* which will display a blank value, and are not guaranteed to work ***/
user_pref("privacy.sanitize.timeSpan", 0);
/*** [SECTION 4000]: FPP (fingerprintingProtection)
RFP (4501) overrides FPP
In FF118+ FPP is on by default in private windows (4001) and in FF119+ is controlled
by ETP (2701). FPP will also use Remote Services in future to relax FPP protections
on a per site basis for compatibility (4004).
https://searchfox.org/mozilla-central/source/toolkit/components/resistfingerprinting/RFPTargetsDefault.inc
https://support.mozilla.org/en-US/kb/firefox-protection-against-fingerprinting#w_how-does-each-protection-work
[NOTE] RFPTargets + granular overrides are somewhat experimental and may produce unexpected results
- e.g. FrameRate can only be controlled per process, not per origin
1826408 - restrict to system fonts (kBaseFonts + kLangPackFonts) (Windows, Mac, some Linux) (FF119+)
1928705: android (FF134+)
https://searchfox.org/mozilla-central/search?path=StandardFonts*.inc
1858181 - subtly randomize canvas per eTLD+1, per session and per window-mode (FF120+)
1887682 - use fdlibm's sin, cos and tan in jsmath (FF134+)
1954194 - available screen resolution: return a fixed offset height from screen per platform when not full screen (FF143+)
1984333 - hardwareConcurrency: less than 8 return 4 else return 8 (FF143+)
1977836 - maxTouchPoints: return multi-touch as 5 (FF143+)
1917607 - subtly randomize WebGL's readPixels (FF145+)
***/
user_pref("_user.js.parrot", "4000 syntax error: the parrot's bereft of life!");
/* 4001: enable FPP in PB mode [FF114+]
* [NOTE] In FF119+, FPP for all modes (7016) is enabled with ETP Strict (2701) ***/
// user_pref("privacy.fingerprintingProtection.pbmode", true); // [DEFAULT: true]
/* 4002: set global FPP overrides [FF114+]
* uses "RFPTargets" [1] which despite the name these are not used by RFP
* e.g. "+AllTargets,-CSSPrefersColorScheme,-JSDateTimeUTC" = all targets but allow prefers-color-scheme and do not change timezone
* e.g. "-AllTargets,+CanvasRandomization,+JSDateTimeUTC" = no targets but do use FPP canvas and change timezone
* [NOTE] Not supported by arkenfox. Either use RFP or FPP at defaults
* [1] https://searchfox.org/mozilla-central/source/toolkit/components/resistfingerprinting/RFPTargets.inc ***/
// user_pref("privacy.fingerprintingProtection.overrides", "");
/* 4003: set granular FPP overrides
* JSON format: e.g."[{\"firstPartyDomain\": \"netflix.com\", \"overrides\": \"-CanvasRandomization,-FrameRate,\"}]"
* [NOTE] Not supported by arkenfox. Either use RFP or FPP at defaults ***/
// user_pref("privacy.fingerprintingProtection.granularOverrides", "");
/* 4004: disable remote FPP overrides [FF127+] ***/
// user_pref("privacy.fingerprintingProtection.remoteOverrides.enabled", false);
/*** [SECTION 4500]: OPTIONAL RFP (resistFingerprinting)
RFP overrides FPP (4000)
FF128+ Arkenfox by default uses FPP (automatically enabled with ETP Strict). For most people
this is all you need. To use RFP instead, add RFP (4501) to your overrides, and optionally
add letterboxing (4504), spoof_english (4506), and WebGL (4520).
RFP is an all-or-nothing buy in: you cannot pick and choose what parts you want
[WARNING] DO NOT USE extensions to alter RFP protected metrics
418986 - limit window.screen & CSS media queries (FF41)
FF56
1333651 - spoof User Agent & Navigator API
JS: spoofed as Windows 10, OS X 10.15, Android 10, or Linux
HTTP Header: spoofed as Windows 10 or Android 10 until FF136 then matches JS spoof
1369319 - disable device sensor API
1369357 - disable site specific zoom
1337161 - hide gamepads from content
1372072 - spoof network information API as "unknown" when dom.netinfo.enabled = true
1333641 - reduce fingerprinting in WebSpeech API
FF57
1369309 - spoof media statistics
1382499 - reduce screen co-ordinate fingerprinting in Touch API
1217290 & 1409677 - enable some fingerprinting resistance for WebGL
1354633 - limit MediaError.message to a whitelist
FF58+
1372073 - spoof/block fingerprinting in MediaDevices API (FF59)
Spoof: enumerate devices as one "Internal Camera" and one "Internal Microphone"
Block: suppresses the ondevicechange event
1039069 - warn when language prefs are not set to "en*" (FF59)
1222285 & 1433592 - spoof keyboard events and suppress keyboard modifier events (FF59)
Spoofing mimics the content language of the document. Currently it only supports en-US.
Modifier events suppressed are SHIFT and both ALT keys. Chrome is not affected.
1459089 - disable OS locale in HTTP Accept-Language headers (ANDROID) (FF62)
1479239 - return "no-preference" with prefers-reduced-motion (FF63)
1492766 - spoof pointerEvent.pointerid (FF65)
1485266 - disable exposure of system colors to CSS or canvas (FF67)
1494034 - return "light" with prefers-color-scheme (FF67)
1564422 - spoof audioContext outputLatency (FF70)
1595823 - return audioContext sampleRate as 44100 (FF72)
1607316 - spoof pointer as coarse and hover as none (ANDROID) (FF74)
1621433 - randomize canvas (previously FF58+ returned an all-white canvas) (FF78)
1506364 - return "no-preference" with prefers-contrast (FF80)
1653987 - limit font visibility to bundled and "Base Fonts" (Windows, Mac, some Linux) (FF80)
1461454 - spoof smooth=true and powerEfficient=false for supported media in MediaCapabilities (FF82)
531915 - use fdlibm's sin, cos and tan in jsmath (FF93, ESR91.1)
1692609 - reduce JS timing precision to 16.67ms (previously FF55+ was 100ms) (FF102)
1422237 - return "srgb" with color-gamut (FF110)
1794628 - return "none" with inverted-colors (FF114)
1787790 - normalize system fonts (FF128)
1835987 - spoof timezone as Atlantic/Reykjavik (previously FF55+ was UTC) (FF128)
1656377 - spoof pointerEvents azimuthAngle and altitudeAngle (FF131)
1826051 & 1957658 & 2021715 - spoof/suppress Pointer Events, spoof maxTouchPoints (FF132, FF143/ESR140.2, FF150)
previously FF64+ (1363508) it always returned maxTouchPoints as 0
FF132: 0 = mac | 10 = windows, linux, mobile
FF143: 0 = mac, linux | 10 = windows | 5 = mobile | no longer spoof touch PointerEvents | backported to ESR140.2
FF150: 5 = linux
1834307 - always use smooth scrolling (FF132)
1918202 - spoof screen orientation based on spoofed screen size and platform (FF132)
previously FF50+ it always returned landscape-primary and an angle of 0
1390465 - load all subtitles in WebVTT (Video Text Tracks) (FF133)
1873382 - make spoofed devicePixelRatio and CSS media queries match (FF133)
previously FF41+ devicePixelRatio was hardcoded as 1 and FF127+ as 2
previously FF41+ CSS media queries were spoofed as zoom level at a devicePixelRatio of 1
1955425 - return 128 for WebGPU subgroupMaxSize (FF138)
1966860 - spoof WebGL debug renderer info (FF140)
previously FF60+ it was disabled
1781277 - return 10GiB for storage estimate until persistent-storage granted (FF142, ESR140.1)
1972600 - spoof network connection for HTMLMediaElement preload (FF142, ESR140.1)
1975851 - return true for navigator.onLine (FF142, ESR140.1)
1973265 - disable WebCodecs API (FF142)
1984333 - spoof navigator.hardwareConcurrency as 4 except mac return 8 (FF143)
previously FF55+ it returned 2
1999126 - enforce navigator.pdfViewerEnabled as true and plugins/mimeTypes as hard-coded values (FF147)
***/
user_pref("_user.js.parrot", "4500 syntax error: the parrot's popped 'is clogs");
/* 4501: enable RFP
* [NOTE] pbmode applies if true and the original pref is false
* [SETUP-WEB] RFP can cause some website breakage: mainly canvas, use a canvas site exception via the urlbar.
* RFP also has a few side effects: mainly that timezone is GMT, and websites will prefer light theme ***/
// user_pref("privacy.resistFingerprinting", true); // [FF41+]
// user_pref("privacy.resistFingerprinting.pbmode", true); // [FF114+]
/* 4502: set RFP new window size max rounded values [FF55+]
* [SETUP-CHROME] sizes round down in hundreds: width to 200s and height to 100s, to fit your screen
* [1] https://bugzilla.mozilla.org/1330882 ***/
user_pref("privacy.window.maxInnerWidth", 1600);
user_pref("privacy.window.maxInnerHeight", 900);
/* 4503: disable mozAddonManager Web API [FF57+]
* [NOTE] To allow extensions to work on AMO, you also need 2662
* [1] https://bugzilla.mozilla.org/buglist.cgi?bug_id=1384330,1406795,1415644,1453988 ***/
user_pref("privacy.resistFingerprinting.block_mozAddonManager", true);
/* 4504: enable letterboxing [FF67+]
* Dynamically resizes the inner window by applying margins in stepped ranges [2]
* If you use the dimension pref, then it will only apply those resolutions.
* The format is "width1xheight1, width2xheight2, ..." (e.g. "800x600, 1000x1000")
* [SETUP-WEB] This is independent of RFP (4501). If you're using RFP, but dislike the
* margins, then don't enable this pref, keeping in mind that it is effectively fingerprintable
* [WARNING] DO NOT USE: the dimension pref is only meant for testing
* [1] https://bugzilla.mozilla.org/1407366
* [2] https://hg.mozilla.org/mozilla-central/rev/7211cb4f58ff#l5.13 ***/
// user_pref("privacy.resistFingerprinting.letterboxing", true); // [HIDDEN PREF]
// user_pref("privacy.resistFingerprinting.letterboxing.dimensions", ""); // [HIDDEN PREF]
/* 4505: disable RFP by domain [FF91+]
* [NOTE]: The pref takes comma separated values: e.g. "*domain1.tld, *domain2.tld"
* Working domain examples: "arkenfox.github.io", "*github.io"
* Non-working domain examples: "https://arkenfox.github.io", "github.io", "*arkenfox.github.io" ***/
// user_pref("privacy.resistFingerprinting.exemptedDomains", "*.example.invalid");
/* 4506: disable RFP spoof english prompt [FF59+]
* 0=prompt, 1=disabled, 2=enabled
* [NOTE] When changing from value 2, preferred languages ('intl.accept_languages') is not reset.
* [SETUP-WEB] when enabled, sets 'en-US, en' for displaying pages and 'en-US' as locale.
* [SETTING] General>Language>Choose your preferred language for displaying pages>Choose>Request English... ***/
user_pref("privacy.spoof_english", 1);
/* 4507: skip browser.startup.blankWindow if RFP is used [FF136+] ***/
// user_pref("privacy.resistFingerprinting.skipEarlyBlankFirstPaint", true); // [DEFAULT: true]
/* 4510: enforce Contrast Control off [FF138+]
* 0=automatic, 1=off, 2=custom
* [SETTING] General>Language and Appearance>Contrast Control ***/
// user_pref("browser.display.document_color_use", 1); // [DEFAULT: 1 NON-WINDOWS]
/* 4511: disable using system accent colors ***/
user_pref("widget.non-native-theme.use-theme-accent", false); // [DEFAULT: false WINDOWS]
/* 4512: enforce links targeting new windows to open in a new tab instead
* 1=most recent window or tab, 2=new window, 3=new tab
* Stops malicious window sizes and some screen resolution leaks.
* You can still right-click a link and open in a new window
* [SETTING] General>Tabs>Open links in tabs instead of new windows
* [1] https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/9881 ***/
user_pref("browser.link.open_newwindow", 3); // [DEFAULT: 3]
/* 4513: set all open window methods to abide by "browser.link.open_newwindow" (4512)
* [1] https://searchfox.org/mozilla-central/source/dom/tests/browser/browser_test_new_window_from_content.js ***/
user_pref("browser.link.open_newwindow.restriction", 0);
/* 4520: disable WebGL (Web Graphics Library) ***/
// user_pref("webgl.disabled", true);
/*** [SECTION 5000]: OPTIONAL OPSEC
Disk avoidance, application data isolation, eyeballs...
***/
user_pref("_user.js.parrot", "5000 syntax error: the parrot's taken 'is last bow");
/* 5001: start Firefox in PB (Private Browsing) mode
* [NOTE] In this mode all windows are "private windows" and the PB mode icon is not displayed
* [NOTE] The P in PB mode can be misleading: it means no "persistent" disk state such as history,
* caches, searches, cookies, localStorage, IndexedDB etc (which you can achieve in normal mode).
* In fact, PB mode limits or removes the ability to control some of these, and you need to quit
* Firefox to clear them. PB is best used as a one off window (Menu>New Private Window) to provide
* a temporary self-contained new session. Close all private windows to clear the PB session.
* [SETTING] Privacy & Security>History>Custom Settings>Always use private browsing mode
* [1] https://wiki.mozilla.org/Private_Browsing
* [2] https://support.mozilla.org/kb/common-myths-about-private-browsing ***/
// user_pref("browser.privatebrowsing.autostart", true);
/* 5002: disable memory cache
* capacity: -1=determine dynamically (default), 0=none, n=memory capacity in kibibytes ***/
// user_pref("browser.cache.memory.enable", false);
// user_pref("browser.cache.memory.capacity", 0);
/* 5003: disable saving passwords
* [NOTE] This does not clear any passwords already saved
* [SETTING] Privacy & Security>Logins and Passwords>Ask to save logins and passwords for websites ***/
// user_pref("signon.rememberSignons", false);
/* 5004: disable permissions manager from writing to disk [FF41+] [RESTART]
* [NOTE] This means any permission changes are session only
* [1] https://bugzilla.mozilla.org/967812 ***/
// user_pref("permissions.memory_only", true); // [HIDDEN PREF]
/* 5005: disable intermediate certificate caching [FF41+] [RESTART]
* [NOTE] This affects login/cert/key dbs. The effect is all credentials are session-only.
* Saved logins and passwords are not available. Reset the pref and restart to return them ***/
// user_pref("security.nocertdb", true);
/* 5006: disable favicons in history and bookmarks
* [NOTE] Stored as data blobs in favicons.sqlite, these don't reveal anything that your
* actual history (and bookmarks) already do. Your history is more detailed, so
* control that instead; e.g. disable history, clear history on exit, use PB mode
* [NOTE] favicons.sqlite is sanitized on Firefox close ***/
// user_pref("browser.chrome.site_icons", false);
/* 5007: exclude "Undo Closed Tabs" in Session Restore ***/
// user_pref("browser.sessionstore.max_tabs_undo", 0);
/* 5008: disable resuming session from crash
* [TEST] about:crashparent ***/
// user_pref("browser.sessionstore.resume_from_crash", false);
/* 5009: disable "open with" in download dialog [FF50+]
* Application data isolation [1]
* [1] https://bugzilla.mozilla.org/1281959 ***/
// user_pref("browser.download.forbid_open_with", true);
/* 5010: disable location bar suggestion types
* [SETTING] Search>Address Bar>When using the address bar, suggest ***/
// user_pref("browser.urlbar.suggest.history", false);
// user_pref("browser.urlbar.suggest.bookmark", false);
// user_pref("browser.urlbar.suggest.openpage", false);
// user_pref("browser.urlbar.suggest.topsites", false); // [FF78+]
/* 5011: disable location bar dropdown
* This value controls the total number of entries to appear in the location bar dropdown ***/
// user_pref("browser.urlbar.maxRichResults", 0);
/* 5012: disable location bar autofill
* [1] https://support.mozilla.org/kb/address-bar-autocomplete-firefox#w_url-autocomplete ***/
// user_pref("browser.urlbar.autoFill", false);
/* 5013: disable browsing and download history
* [NOTE] We also clear history and downloads on exit (2811+)
* [SETTING] Privacy & Security>History>Custom Settings>Remember browsing and download history ***/
// user_pref("places.history.enabled", false);
/* 5014: disable Windows jumplist [WINDOWS] ***/
// user_pref("browser.taskbar.lists.enabled", false);
// user_pref("browser.taskbar.lists.frequent.enabled", false);
// user_pref("browser.taskbar.lists.recent.enabled", false);
// user_pref("browser.taskbar.lists.tasks.enabled", false);
/* 5016: discourage downloading to desktop
* 0=desktop, 1=downloads (default), 2=custom
* [SETTING] To set your custom default "downloads": General>Downloads>Save files to ***/
// user_pref("browser.download.folderList", 2);
/* 5017: disable Form Autofill
* If .supportedCountries includes your region (browser.search.region) and .supported
* is "detect" (default), then the UI will show. Stored data is not secure, uses JSON
* [SETTING] Privacy & Security>Forms and Autofill>Autofill addresses
* [1] https://wiki.mozilla.org/Firefox/Features/Form_Autofill ***/
// user_pref("extensions.formautofill.addresses.enabled", false); // [FF55+]
// user_pref("extensions.formautofill.creditCards.enabled", false); // [FF56+]
/* 5018: limit events that can cause a pop-up ***/
// user_pref("dom.popup_allowed_events", "click dblclick mousedown pointerdown");
/* 5019: disable page thumbnail collection ***/
// user_pref("browser.pagethumbnails.capturing_disabled", true); // [HIDDEN PREF]
/* 5020: disable Windows native notifications and use app notications instead [FF111+] [WINDOWS] ***/
// user_pref("alerts.useSystemBackend.windows.notificationserver.enabled", false);
/*** [SECTION 5500]: OPTIONAL HARDENING
Not recommended. Overriding these can cause breakage and performance issues,
they are mostly fingerprintable, and the threat model is practically nonexistent
***/
user_pref("_user.js.parrot", "5500 syntax error: this is an ex-parrot!");
/* 5501: disable MathML (Mathematical Markup Language) [FF51+]
* [1] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=mathml ***/
// user_pref("mathml.disabled", true); // 1173199
/* 5502: disable in-content SVG (Scalable Vector Graphics) [FF53+]
* [1] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=firefox+svg ***/
// user_pref("svg.disabled", true); // 1216893
/* 5503: disable graphite
* [1] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=firefox+graphite
* [2] https://en.wikipedia.org/wiki/Graphite_(SIL) ***/
// user_pref("gfx.font_rendering.graphite.enabled", false);
/* 5504: disable asm.js [FF22+]
* [1] http://asmjs.org/
* [2] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=asm.js
* [3] https://rh0dev.github.io/blog/2017/the-return-of-the-jit/ ***/
// user_pref("javascript.options.asmjs", false);
/* 5505: disable Ion and baseline JIT to harden against JS exploits [RESTART]
* [NOTE] When both Ion and JIT are disabled, and trustedprincipals
* is enabled, then Ion can still be used by extensions (1599226)
* [1] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=firefox+jit
* [2] https://microsoftedge.github.io/edgevr/posts/Super-Duper-Secure-Mode/ ***/
// user_pref("javascript.options.ion", false);
// user_pref("javascript.options.baselinejit", false);
// user_pref("javascript.options.jit_trustedprincipals", true); // [FF75+] [HIDDEN PREF]
/* 5506: disable WebAssembly [FF52+]
* Vulnerabilities [1] have increasingly been found, including those known and fixed
* in native programs years ago [2]. WASM has powerful low-level access, making
* certain attacks (brute-force) and vulnerabilities more possible
* [STATS] ~0.2% of websites, about half of which are for cryptomining / malvertising [2][3]
* [1] https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=wasm
* [2] https://spectrum.ieee.org/tech-talk/telecom/security/more-worries-over-the-security-of-web-assembly
* [3] https://www.zdnet.com/article/half-of-the-websites-using-webassembly-use-it-for-malicious-purposes ***/
// user_pref("javascript.options.wasm", false);
/* 5507: disable rendering of SVG OpenType fonts ***/
// user_pref("gfx.font_rendering.opentype_svg.enabled", false);
/* 5508: disable all DRM (Digital Rights Management) content (EME: Encryption Media Extension)
* Optionally hide the UI setting which also disables the DRM prompt
* [SETTING] General>DRM Content>Play DRM-controlled content
* [TEST] https://bitmovin.com/demos/drm
* [1] https://www.eff.org/deeplinks/2017/10/drms-dead-canary-how-we-just-lost-web-what-we-learned-it-and-what-we-need-do-next ***/
// user_pref("media.eme.enabled", false);
// user_pref("browser.eme.ui.enabled", false);
/* 5509: disable IPv6 if using a VPN
* This is an application level fallback. Disabling IPv6 is best done at an OS/network
* level, and/or configured properly in system wide VPN setups.
* [NOTE] PHP defaults to IPv6 with "localhost". Use "php -S 127.0.0.1:PORT"
* [SETUP-WEB] PR_CONNECT_RESET_ERROR
* [TEST] https://ipleak.org/
* [1] https://www.internetsociety.org/tag/ipv6-security/ (Myths 2,4,5,6) ***/
// user_pref("network.dns.disableIPv6", true);
/* 5510: control when to send a cross-origin referer
* 0=always (default), 1=only if base domains match, 2=only if hosts match