Firefox Configuration Guide for Privacy Freaks and Performance Buffs

Want to configure Firefox and other Gecko-based browsers for better performance and security?

See the revision history at the end for a list of changes.

Before embarking on this journey into the bowels of Firefox, you may want to first read, Tor verses a VPN – Which is right for you?. If you choose to use the Tor Browser, you need not digest this guide.

Introduction

This guide is long, boring, dry, tedious and somewhat technical, so if you don't feel comfortable digesting it, try the The Firefox Privacy Guide For Dummies! instead, however be aware that it doesn't offer the same degree of protection.

To understand my personal position regarding the ethical nature of the Mozilla Foundation, read The Mozilla Monster.

WARNING: This guide is not for use with the Tor browser. Configuring the Tor browser as outlined in this guide will result in potentially serious risks to your privacy.

Though this guide is centered around the Firefox web browser, users of other browsers, email clients and Mozilla products may find it useful. If you are interested in hardening the Thunderbird email client, see The Thunderbird Privacy Guide for Dummies!.

Many of us are aware of the immense threats to our on-line privacy and security posed by various technology companies, governments and malicious hackers, any of which may go to great lengths to monitor our electronic communications. Governments and their "intelligence" apparatuses not only spy on each other, but on the citizenry as well and they leverage the services of various companies to do so, including Microsoft, Google, Facebook, Verizon, Comcast and Amdocs as well as many, many others. While the data these companies collect may be used for relatively benign purposes such as targeted advertising, the intentions are often far more sinister. Much of what Edward Snowden has brought to light is not new, but it seems the information has been presented in a way that has captured the attention of the public, prompting many to seek ways to mitigate the threats.

While the primary goal of this guide is to help the reader thwart some of the more obvious efforts to track and profile us as we surf the web, as well as increase browser security and performance, understand that i am not an expert in computer security or privacy and there are surely many more variables and vectors for attack than i am aware of. While there are many known methods that can be used to compromise our digital well being, how many more are there of which we know nothing? Or what about techniques that most of us never consider? For example, even if you are a knowledgeable, technically proficient and privacy conscious individual who uses open hardware devices running open source software and a security enhanced operating system, and even if you connect to the internet only through Tor, you may still be at risk of being tracked because, disregarding everything else, your unique writing style can be used to identify you. It is not this level of sophistication that i will attempt to address here however. My goal is to share what i have learned over the years as a casual web surfer and computer user who has a hobbyist-grade interest in computer security and digital privacy. Having said that, i believe -- and please correct me if i'm wrong -- this guide is currently one of the more comprehensive of its kind in that it addresses many aspects of the Firefox browser including configuration, extensions and optimizations. If you want to go further than this guide can carry you, see the resources section at the end which include the fine article, Improve Your Privacy in the Age of Mass Surveillance. I would also highly recommend using a VPN to help prevent spying by your ISP and other bad actors. That One Privacy Site is a good resource for choosing a VPN, as is TorrentFreak which publishes annual reports regarding many of the popular VPN service providers. Their 2018 report is here.

As with any modern and mainstream web browser, Mozilla Firefox is a highly complex beast consisting of millions of lines of code and hundreds of configuration options, many of which are interlinked, hidden, or undocumented. Things can go down the toilet real fast if you start messing around with its settings willy-nilly and poorly coded add-ons can compound the problem. Here we will attempt to accomplish our goals in an efficient manner with a minimal number of carefully chosen browser extensions, or add-ons.

A bit of a trade-off must be expected when we tighten security and privacy insomuch as some websites will cease to function properly until the settings for those specific sites are adjusted. Anyone who has used a content filter such as NoScript or Request Policy will understand that certain resources must be allowed for a given website to function in an acceptable way. Similar to NoScript however, the process of allowing required resources usually consists of a mouse click or three followed by a page refresh and once we have made the necessary adjustments for our favorite websites, our workload will be greatly reduced. Nevertheless, be prepared to put a little more effort into your web surfing activities in general and expect the occasional hard-case where more fiddling than usual will be required to get a particular site working properly. The pay-off is a much cleaner and faster web that is less able to track and profile us, as well as a somewhat hardened and speedier Firefox that is more resistant to attack.

Terminology

Add-on/extension: I use these terms interchangeably. A web browser add-on or extension is a piece of software typically developed by a 3rd party that extends the capability of the browser. Web extensions, which leverage the WebExtension API (Application Programming Interface), have replaced the older legacy (XUL/XPCOM) extensions beginning with Firefox version 57. This newer type is essentially the same format as used by Google Chrome and other web browsers. Unfortunately the WebExtension API is severely limited. For example, such extensions cannot modify the GUI (Graphic User Interface) of Firefox in the same way legacy extensions could.

AMO: addons.mozilla.org, the Mozilla Add-ons website.

Browser fingerprinting: Web servers can employ a wide variety of methods to uniquely identify your web browser, hardware and software configuration, collectively known as fingerprinting. Fingerprint data may consist of many bits of information about your environment which, when combined, can be used to uniquely identify a web browser. This information may include such things as the browser viewport dimensions, installed add-ons, its capabilities, your locale, your operating system, querying the browser cache, your display resolution and much more. This information can be gleaned using various techniques, including through HTTP header information, JavaScript, and others, and it is often used for the purpose of tracking and profiling the user and their web activities. For further information, see A Primer on Information Theory and Privacy and Panopticlick. See also the explanation for 'tracking' and 'web storage' below.

Crapware/malware: I consider crapware/malware to be software which contains code which is not relevant to the functionality users expect. As such the term crapware, or malware, refers largely to adware, tracking code and other malicious code with regard to web browser extensions. Crapware is often added to browser extensions by a company or solo developer who wishes to monetize their work and often takes the form of profiling users and selling the data collected by the extension to a marketing company, however much worse is possible.

CDN: A Content Delivery Network is a service that hosts reusable content, such as graphics and reusable scripts which developers can leverage to make building web platforms easier. CDNs often present a threat to our privacy by tracking our web activities. They are perhaps a most formidable threat because a single CDN service may be used by many millions of popular websites and therefore the spying capabilities of the company providing the CDN service can be widespread and cross-domain in nature. The use of CDNs is prolific today and since many websites will not function without the content they deliver, globally blocking CDN content is hardly an option.

CSS: Cascading Style Sheets are used primarily to apply visual styling to HTML elements, thus making web pages look pretty, however the capability of CSS has been expanded well beyond its original specifications to the point where it can now be used for nefarious purposes.

Domain/subdomain/TLD: In the example 'sub.example.com', 'example' is the root domain, 'sub' is a subdomain of the root domain and 'com' is the TLD, or Top Level Domain. You can think of root domains and subdomains as sort of different containers which are used to separate content for a single website. For example, let's say kitties.com is focused primarily on information about kittens, but they also might have a web store where they sell paper bags. In order to keep the store content separate, they may host the store on the subdomain 'shop.kitties.com'.

Fingerprinting: Fingerprinting is the technique of developing a unique signature that can be used to identify and track the browser within a domain, across domains, and even across sessions. There are many ways to fingerprint a browser including by installed fonts and how they are rendered, the dimensions of the the browser view port, the Canvas API, web storage and more. Many fingerprinting techniques rely upon JavaScript.

HTTP/HTTPS: Hypertext Transfer Protocol and Hypertext Transfer Protocol Secure are communication protocols used by computers to transmit data over the internet. For HTTP an insecure, unencrypted connection is established which is vulnerable to ISP (Internet Service Provider) snooping and man-in-the-middle attacks, while a secure, encrypted connection is established with HTTPS. Some web servers simply do not support HTTPS and for this reason i will again point out the necessity of using a VPN.

JavaScript (JS): A powerful programming language that runs code within the browser, often to make pages interactive. Although JavaScript is used by many websites for legitimate reasons, it can and often is used maliciously to perform a wide variety of attacks against the browser and our privacy. Many browser fingerprinting/tracking techniques depend on JavaScript being enabled and this is the default in every mainstream web browser.

Tracking: Once a unique identity for the browser is established through fingerprinting, cookies, storage, or other methods, it is then possible to track its activity both within the same domain and across domains. See also the explanation for 'web storage' below.

Web fonts/remote fonts: These are font packages typically hosted by a 3rd party, such as Google, which a web developer may use to specify how text is displayed on a website. Web fonts present a few problems regarding browser tracking and security.

Web server: For the purpose of this document, a web server is a computer that is connected to the internet which hosts (serves) one or more websites.

Web storage: In addition to HTTP cookies and web caching, most/all popular web browsers also allow a web server to store data locally using several storage methods including local and session storage, indexedDB storage, window.name storage, Etag cache storage, Local Shared Objects storage, Service Workers, offline storage, HTTP Strict Transport Security storage and other methods. Stored data for Firefox may consume up to 50% of your free disk space. If you are concerned about protecting your privacy, you have far more to worry about than the simple text cookies of yesteryear which in theory, but not always in practice, could be read only by the domain that set them and this problem only seems to worsen as the web grown more complex.

Prerequisites

Code editor

You will need a decent code editor with syntax highlighting to edit Firefox's configuration files. Linux users should have something suitable installed by default, however if you're running Windows i might suggest Notepad++ or PSPad, the latter being the simpler of the two.

Unhide file extensions

If Windows is using you, the geniuses at Microsoft have taken it upon themselves to hide file extensions from the user. You will need to un-do that.

Getting Firefox

Though i recommend using the stable release version of Firefox, there are other versions such as the ESR (Extended Support Release), however it is usually an older version. There is also a Developer Edition which includes the very latest features (and bugs). While there are many 3rd party forks of Firefox, including Waterfox, Cyberfox, Pale Moon (or Basilisk from the same developer), etc., i do not recommend using any of them. The small development teams for these 3rd party builds often lag far behind regarding security patches and they can be buggy and incompatible with the latest add-ons (Pale Moon doesn't support the newer Web Extensions at all). While some forks may be more privacy-centric out of the box, we can accomplish essentially the same degree of privacy or better with the official Mozilla release version.

The user.js file

The user.js file is typically where your personal Firefox preferences are best kept, however in our case we will be using a preconfigured one and then storing our personal preferences in a user-overrides.js file which will be appended to user.js using a script.

The user.js file we will use is a result of a formidable effort by 'pants' and the rest of the 'ghacks-user.js' crew and contributors. Their work became rather popular when it was published as A comprehensive list of Firefox privacy and security settings by Martin Brinkmann on ghacks.net. The project has since moved GitHub, but don't download anything yet.

Firefox post install cleanup

After installing Firefox, and before you make any changes, back-up your current profile. If you don't know where it is, enter about:profiles in the address bar and click the 'Open Directory' button in the 'Root Directory' row. The easiest way to backup your profile is to select your profile folder under the /firefox directory and press Ctrl+C to copy the folder, then Ctrl+V to paste it in the same place but with a different name. I might suggest keeping the original name and just appending -bak to the copy. From this point on, all changes should be made to your original profile, leaving your backup profile untouched in case something explodes. Next, delete everything from your original profile, keeping only your bookmarks and whatever else you need. See the article Profiles - Where Firefox stores your bookmarks, passwords and other user data if you need help with what data is stored in which file/folder.

System add-ons

Packaged with Firefox are a bunch of system add-ons which are installed without your consent and they are essentially hidden (they are not listed in about:addons). Some of these add-ons have been and may currently be used for controversial purposes such as collecting data about how users interact with search engines, the browser, etc.. Typically i remove all of them, however you may want to keep some them after researching what they do and whether they preserve your privacy. On Linux these add-ons may be found at /usr/lib/firefox/browser/features and for Windows in \Program Files (x86)\Firefox\browser\features or \Program Files\Firefox\browser\features. You can delete them in Linux using the terminal:

cd /usr/lib/firefox/browser/features
sudo rm *.xpi

These system add-ons will be reinstalled each time Firefox is upgraded. On Windows you can apparently use CCleaner to disable them. If you're running Linux with the pacman package manager (Arch, Manjaro), you can prevent their re-installation by editing the pacman configuration file, pacman.conf. Note that this will not work using Pamac, the GUI package manager, until this bug is addressed. In my case i find it easier to just bookmark the /features folder in my file manager and run the command above each time i update Firefox.

Search engines

I recommend reading Firefox Search Engine Cautions and Recommendations which offers information about how Mozilla monetizes Firefox with the included search engine plugins and what can be done to opt out of this affiliate scheme should you so choose.

Required add-ons and settings

Following are the add-ons required for this guide and their recommended settings. All of the add-ons listed here are of the WebExtension variety, meaning most should work with Firefox versions 57 to 59 and all should work with versions 60 and up. Download and configure each add-on as you go through the list. Each of these add-ons is important so don't skip any of them with the possible exception of uMatrix.

Note that there is a serious problem with Firefox regarding Content Security Policy (CSP) which has yet to be addressed by Mozilla. The short version is that, when two or more add-ons use CSP injection to modify HTTP headers, and many do, only one will succeed. For example, both uBlock Origin and uMatrix leverage CSP, as well as other suggested add-ons here. In some cases the use of CSP can be disabled in add-on settings and i have noted this in the suggested settings. Also see the Extensions section of the 'ghacks' wiki. Please create an account at Bugzilla and vote for this issue.

CanvasBlocker by kkapsner

Description: Helps to prevent browser fingerprinting through the JavaScript Canvas APIs.

Settings: Following are the most important settings. Others are optional.

General tab:

  • Expert mode: enabled
  • Block mode: fake
  • Faking
    • Random number generator: non-persistent
  • Notifications
    • Show notification icon: enabled

API tab:

  • Canvas API
    • Protected part of the canvas API: readout
    • Protected API features: all options enabled
  • Audio API
    • Protect audio API: enabled
    • Protected API features: all options enabled
  • History API
    • Protected API features: all options enabled
  • Window API
    • Protect window API: enabled
    • Protected API features: all options enabled
  • DOMRect API
    • Protect DOMRect API: enabled
    • Protected API features: all options enabled

Misc tab:

  • Block data URL paged: disabled (CSP issue)
  • Logging level: error

ClearURLs by Kevin R.

Description: Strips many tracking and other (mostly) unnecessary parameters from hyperlinks, such as the utm_* tracking parameters used by Google Analytics. Unlike other similar extensions, ClearURLs uses a remotely updated list from GitLab and requires little or no interaction.

Settings: Following are the most important settings. Others are optional.

  • Allow domain blocking: if you are not using any of the major ad filtering lists in uBlock, then enable this
  • Skip URLs on local hosts
  • Prevent tracking injection over history API
  • Block hyperlink auditing
  • Filters ETag headers from requests

CSS Exfil Protection by Mike Gualtieri

Description: Helps to prevent attackers from exploiting Cascading Style Sheets (CSS) vulnerabilities.

Settings: None.

HTTPZ by claustromaniac

Description: Attempts to force websites to use an encrypted connection (HTTPS) but will fall back to an unencrypted connection (HTTP) if the website does not support HTTPS.

Settings:

  • The default settings are fine. You can disable 'Fallback to HTTP without warning' if you want HTTPZ to be notified when HTTPZ is unable to upgrade an HTTP request.

LocalCDN by nobody42

Description: Helps to prevent tracking and speeds-up page loading by using local copies of common JavaScript libraries rather than fetching them from a CDN.

Settings: Following are the most important settings. Others are optional.

  • Display injection counts on icon
  • Disable link prefetching
  • Strip metadata from allowed requests

Enabling the option to 'Block requests for missing resources' will further decrease threats to privacy, however this will break more websites as well and so the choice is yours.

Privacy-Oriented Origin Policy (POOP) by claustromaniac

Description: Helps to protect privacy by manipulating Cross-Origin Resource Sharing (CORS) requests.

Settings: I would recommend setting the 'Global mode' to 'aggressive' and enabling the 'Exclude root domain matches' option. If you not are using uMatrix, enable the 'Spoof cross-origin Referer' option. You can also add the following to the 'exclude requests using patterns' area:

www.youtube.com *.googlevideo.com
www.youtube-nocookie.com *.googlevideo.com
*.dailymotion.com *.dmcdn.net

Site Bleacher by wooque

Description: Automatically deletes web storage when a domain is revisited. Site Bleacher is the *only* add-on at this time that is capable of clearing IndexedDB storage on a dynamic basis.

Settings: Other than a whitelist there are no settings.

Skip Redirect by Sebastian Blask

Description: Skips link redirections such as used by Google, AMO and many other companies and websites, thus helping to prevent tracking. Redirects are intermediate links, such as 'click-track.com/abc123' or short links, that forward the browser to the final destination.

Settings: The default settings are sufficient. You will likely have to whitelist sites that no longer work properly which Skip Redirect makes easy to do since you can copy the last skipped URL by right-clicking its toolbar icon and then adding that URL or domain to the blacklist.

uBlock Origin (uBO)

Description: uBlock Origin is an excellent ad/content blocker that can use the same filter lists as Adblock Plus as well as many more. Make sure you use the original uBlock Origin by Raymond Hill and no other. If you choose not to use uMatrix, it is important that you enable advanced mode in uBO and learn how to use its dynamic filtering capabilities.

Settings: If you decide to use both uBlock Origin and uMatrix as suggested, the former will be used primarily for its static filtering capability (the filter lists for ads, tracking, malware, etc.) while the latter will be used primarily for its dynamic filtering capability (JS, cookies, frames, etc). To set up uBO, see the uBlock Origin Suggested Settings Guide. and use the settings in the 'Advanced guide settings' column.

uMatrix (uM)

Description: By the same developer as uBlock Origin, uMatrix is also a powerful content blocker that provides more granular control over web requests than uBlock does. Using uMatrix is somewhat optional, however if you choose not to use it then it is important that you enable advanced mode in uBlock Origin and learn how to use its dynamic filtering capabilities.

Settings:

Once uMatrix is installed, click the toolbar button and then the title bar of the pop-up to open the Dashboard.

Following are the settings i recommend enabling.

Settings, Convenience:

  • Show the number of blocked resources on the icon
  • Collapse placeholder of blacklisted elements (but not blocked elements, at least not until you become more comfortable with uM)

A note regarding the option 'Spoof <noscript> tags when 1st-party scripts are blocked': Enabling this setting is entirely optional as there are advantages either way. If you enable it, then some websites will present a notification that you have disabled JavaScript (which we will certainly do) and this can be very helpful, especially to those who are new to blocking JS. On the other hand, some content for some websites that would normally be available with JS disabled will not be available if this option is enabled, so it's your choice as to whether to enable it.

Settings, Privacy:

Note that the three options to delete web storage are not strictly required since Site Bleacher handles this storage, however i think it's better to have the redundancy, plus they both work differently.

  • Delete blocked cookies
  • Delete non-blocked session cookies 60 minutes after the last time they have been used
  • Delete local storage content set by blocked hostnames
  • Clear browser cache every 60 minutes
  • Spoof HTTP referrer string of third-party requests
  • Block all hyperlink auditing attempts

Do not enable the Strict HTTPS option if you're going to use the HTTPZ add-on which i highly recommend you do.

Optionally, on the 'My rules' tab, you can add the following to the 'Temporary rules' pane, then save and commit your change:

no-workers: * true

This will disable web workers which will prevent certain JS from running in the background. If a page breaks as a result, you can enable web workers on a per-site basis from the uM pop-up by clicking the vertical 3 dot icon. One resource this setting will break is videos on the dailymotion.com website. For example, videos from Dailymotion will not play until you allow web-workers for dailymotion.com.

Note that web workers depend on JavaScript being enabled. Also note that blocking workers with uM may be problematic in that, if they were blocked by the Firefox prefs instead, the web page may fall back to one that doesn't depend on workers whereas if they are blocked in uM then the page may just break.

On the 'Assets' tab, disable all of the host file filter lists, purge the caches and save your changes. It is better to use uBlock Origin to control static filtering since it offers many more options by default, plus the hosts filters are more likely to break website functionality.

Also on the 'Assets' tab, you can enable the 'Ruleset recipes for English websites​​​​​​​' option. On the uM toolbar pop-up you will notice a puzzle piece icon which you can use to quickly import a rule-set for resources used by the page you're visiting if it uses a 3rd party resource and if someone has created a rule-set for that resource. For example, if you visit a page with an embedded YouTube video, you can import the rule-set for YouTube instead of configuring the filters manually. You might want to switch to the global scope before doing this so that embedded YouTube videos will play on all websites.

If you're using the Decentraleyes add-on you need to add some rules to the 'My Rules' tab in the Dashboard. When adding the rules, be sure to remove any conflicting rules for the same domains if you have any (you won't if you're starting fresh).

Additional add-ons

For more possibilities regarding add-ons, see Firefox Extensions: My Picks.

Automatic add-on updates

The tl;dr version is: Do NOT enable automatic add-on updates. The longer version follows...

Regarding automatic add-on updates, which is enabled by default in Firefox, this function is disabled in the 'ghacks' user.js file and i would strongly suggest keeping it disabled. Automatic checking for updates is fine and this is enabled in the 'ghacks' user.js, but we do not want Firefox to update add-ons without our explicit consent. The problem here is that developers may, at any time, and without notice, monetize their add-on or sell their work to an unethical 3rd party and this often results in compromising your privacy. Examples of some currently or formerly popular add-ons which contain(ed) such crapware are Abduction, a screen capture utility; Quick Locale Switcher, a language switcher; FasterFox Lite, a largely useless utility which claims to speed-up Firefox but doesn't; BlockSite, a content blocker; Stylish, a very popular utility for changing the appearance of websites, and many, many others. Not all of these extensions contained crapware when they were first introduced which is why i strongly suggest keeping automatic add-on updates disabled and carefully reviewing the change logs, permissions and privacy policies each time an add-on update is available. For more about Firefox add-ons, see Firefox Extensions – My Picks.

Firefox configuration

This guide depends heavily on the 'ghacks' user.js configuration file which alters hundreds of important Firefox preferences related to privacy and security, thus you need not worry about manually configuring anything from the Preferences menu of Firefox other than a search setting which we'll get to. If you choose to not use the 'ghacks' user.js, then your job is likely to be considerably more difficult assuming your goals are similar. Still, you may find it helpful to refer to the 'ghacks' user.js should you choose to start from scratch.

Search bar on navigation bar

I would suggest adding the search bar to the navigation bar and using it instead of the address bar for searching the web. Not only might you find it more convenient, but there are potential privacy concerns when searching from the address bar. To accomplish this, open the Firefox Preferences page, click the Search item on the left, then enable the option 'Add search bar in toolbar'.

Firefox profile in RAM

With the wide adoption of speedy Solid State Drives (SSDs), the concept of sticking the Firefox profile in RAM for performance reasons may seem obsolete, however there are still benefits in doing so. If you don't want to disable disk caching, web storage and cookies globally, and thus break a lot of websites in the process, there will be substantial read and write activity for your storage media. Placing your Firefox profile in RAM will alleviate much of this, however doing so can be risky should a catastrophic failure occur, such as a power failure which could result in data loss or corruption. Fortunately there are ways to minimize this risk. If you use Windows you're on your own since i don't, suffice to say that there exists Windows compatible software that can manage RAM disks and backup your profile to your storage media. 'Bushdoctor' provides a method in a comment left on this article. Those using most any flavor of Linux have access to a very spiffy utility called Profile-sync-daemon (PSD) which is designed specifically for this task and it works with quite a few browsers. Check your package manager to see if it's available in your repository. To get PSD working, run man psd in a terminal or consult the guide on the Arch wiki. Setting it up was very easy in my case and it has worked flawlessly and transparently ever since.

Cache

Note that Firefox stores its web cache in a location other than the profile directory. On Linux it's kept at /home/[user]/.cache/mozilla/firefox/. Normally you would have to deal with web cache separately if you wanted to store it in RAM also, however since disk caching is completely disabled in the 'ghacks' user.js (cache is stored in memory) and the cache is dumped when you exit Firefox, you need not worry about it. If you're thinking it would be more efficient to keep the browser cache instead of having to re-download objects for the websites you visit frequently, you're right, however doing so can compromise your privacy. We won't exactly be dumping all of the browser cache either since we're using the Decentraleyes add-on.

Configuration files

Keep the following hierarchy in mind as you read this section. When Firefox starts:

  1. prefs.js is read by Firefox
  2. user.js is read by Firefox - all preferences in the user.js file are copied to the prefs.js file and any preferences that are duplicated in both files are overridden by those in user.js - prefs.js is then used to generate what you see in about:config
  3. user-overrides.js is never read by Firefox but these preferences are appended to the 'ghacks' user.js with a script (preferred) or by manual copying - if using the 'ghacks' user.js this is the only file you should edit and it is where all your custom preferences should be placed - this may defy conventional knowledge, so let me be clear:

If you are going to use the 'ghacks' user.js file then you should never edit it, (nor the prefs.js file) nor should you change important settings from about:config unless you're only testing something. All of your custom preferences should be placed in your user-overrides.js file and no where else, and then appended to the 'ghacks' user.js using their updater script.

One reason for this is because the 'ghacks' user.js is quite a large file that is updated fairly frequently and if you edit it and then update it, all your custom changes will be lost, whereas if you copy the preferences you want to alter from the 'ghacks' user.js to your user-overrides.js and change the values there, then updating the 'ghacks' user.js one will be a lot less painful. On the other hand, should you choose to not use the 'ghacks' user.js, then you should add your changes to your own user.js and you can ignore everything stated here about the user-overrides.js. Either way, never edit the prefs.js file directly or by way of about:config unless you're just testing something.

If you do not have a general understanding of the the user.js file, you may want to read this on the 'ghacks' wiki. You should also poke around elsewhere in the wiki for detailed information on using and maintaining their user.js file.

Obtaining and maintaining the user preferences files

In your profile folder, delete or rename your existing user.js file if you have one. You can transfer any needed settings later if they are not already covered in the 'ghacks' one. Next, i might suggest downloading my user-overrides.js file. Go to the 12bytes.org/Firefox-user.js-supplement at my Codeberg.org repository and download the user-overrides.js file to your Firefox profile directory. The easiest way to get the file without messing up the formatting is to view the raw file, then press Ctrl+S to save it. Next, open the file for editing using your code editor and follow the instructions within.

Next we want the 'ghacks' user.js file from the ghacksuserjs/ghacks-user.js GitHub repository but you need not download it directly. Instead, grab their updater.sh (Linux) or updater.bat (Windows) script by clicking the file name, then clicking the 'Raw' button in the new page and pressing Ctrl+S to save the file to your Firefox profile directory. Use the same method to get a copy of their prefsCleaner.sh (Linux) or prefsCleaner.bat (Windows) and place it in your Firefox profile directory. This script is used to reset any unused or old preferences in your prefs.js file. If you're running Linux, don't forget to make the files executable. Next, run the updater script to fetch the 'ghacks' user.js and append the contents of your user-overrides.js to it. In Linux run ./updater.sh in a terminal and follow the prompts. If you have given the file the executable flag and still get an error, try grabbing a new copy being careful to use the method i described earlier.

At this point it is important to go through the entire 'ghacks' user.js file and read all of the comments and review each of the settings to be sure everything is configured the way you want. As stated above, any preferences you want to change in the user.js file should be copied to your user-overrides.js file in the appropriate section where you will then change their values. Note that if you ever add and then comment out or delete a custom preference in your user-overrides.js which is not contained in the 'ghacks' user.js, and you have run Firefox after doing so, that setting will remain in the prefs.js file. The safest way to remove such preferences is to open about:config in Firefox and reset them (right-click the preference, click 'Reset').

Over time it is possible that your user-overrides.js file will contain preferences that are obsolete. The 'ghacks' user.js file contains a list of some of these preferences in the section titled [SECTION 9999]: DEPRECATED / REMOVED / LEGACY / RENAMED and these preferences should be removed from your user-overrides.js file. One very tedious way to do this is to go through the list line by line and see if they are duplicated in your user-overrides.js. An easier way is to use the -c switch (documentation here) when you run the updater script which will output a 'diff' file containing the differences between the old user.js and the new one.

IMPORTANT: Don't forget to run the updater script with the -c switch every time you update the user.js file or make changes to the user-overrides.js file. You can read more about the updater script here and the cleaner script here.

Verifying the integrity of user.js

It is important to perform an integrity check whenever the 'ghacks' user.js file is updated or you have changed anything in the user-overrides.js file.

From the 'ghacks' crew:

In FF60+, 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.

They reference the article, 'A New Preferences Parser for Firefox' if you're interested in knowing more.

To perform this check, you might want to disable your network connection, then start Firefox and open the Browser Console from the Web Developer toolbox (Ctrl+Shift+J might work) and check for and preferences errors.

The reason it is suggested to disable your network connection is because, in the event there is a problem with an important preference, a network connection may allow data to flow in or out which you wanted to avoid.

Now we will further check the integrity of the user.js and user-overrides.js files. You may have noticed a bunch of unusual looking _user.js.parrot preferences in both files. These are used for troubleshooting syntax errors by quickly identifying a specific section in which the error lies. When you run Firefox for the first time after updating the user.js or making changes to your user-overrides.js, check the value of the troubleshooting preference by entering about:config in the address bar and searching for the _user.js.parrot preference (it will likely be the first one listed without having to search). The value should match the very last _user.js.parrot preference value in your user-overrides.js or, if you are not using a user-overrides.js, then it should be the last value in the 'ghacks' user.js, "SUCCESS: No no he's not dead, he's, he's restin'!". If the value for the troubleshooting preference is not what you expect, then you can use it to quickly determine in which section of the user.js or user-overrides.js the syntax error lies. While it cannot narrow down the problem to a specific preference or line number, at least you will know where to begin looking.

Updating the user.js and user-overrides.js files

To update the 'ghacks' user.js file just run the updater script with the -c switch as explained earlier. To update my personal user-overrides.js file, just copy the contents of the new version to your user-overrides.js, then run the updater script with the -c switch. Lastly, run the 'ghacks' prefsCleaner script with Firefox closed. To be notified of updates to the 'ghacks' user.js and/or my user-overrides.js files, i strongly suggest subscribing to the following:

HSTS tracking

To understand how HTTP Strict Transport Security (HSTS) works and how it can be used to track browsing history, as well as the implications of disabling it, read How to prevent HSTS tracking in Firefox on the ghacks website. Setting the preference security.cert_pinning.enforcement_level to '0' may disable HSTS and Public Key Pinning, however there is a security risk in doing so. If you set the preference to '0' and experience the error "The server uses key pinning (HPKP) but no trusted certificate chain could be constructed that matches the pinset.", reset the preference. Likewise if you set the preference to '2' and experience the error "MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE", reset the preference.

uMatrix usage

!!! SET THE SCOPE, LOCK THE LOCK !!! Keep that in mind as you read this section.

You will likely be spending far more time with uMatrix (uM) than all the other add-ons combined and, being it is one of the most important ones in the pile, it is vital you understand how to use it, so read the wiki because i'm not going to go into great detail here.

When you first install uMatrix, it will allow all 1st party requests by default and we need to sledgehammer that, so load up 12bytes.org in a new tab and click the uM toolbar icon to display the main pop-up interface:

Because you have read the uMatrik wiki (you did, right?), you already know that YOU MUST REMEMBER TO SET THE SCOPE in which uM operates before making any changes. Failing to do this will threaten your privacy and/or security. You also know that any changes you make are temporary unless you save them. Since we first want to set some basic default filters that affect all websites, we need to change to the global scope:

Once we're operating in the global scope, i suggest setting up uMatrix to allow CSS, images and, if you're using Site Bleacher, 1st party cookies, all globally. Optionally you may want to allow 1st party media and/or frames globally.

The configuration above will result in the following behavior:

  • 1st party cookies will be allowed globally
  • CSS will be allowed globally, including 3rd party CSS
  • Images will be allowed globally, including 3rd party images
  • 1st party frames will be allowed globally

Unless you only want your changes to be temporary, always remember to click the padlock icon to save them.

Note that in the screenshots that follow, the 1st party cookies block will not always be green as in the one above due to an oversight on my part when i created the screenshots.

Now load up this post in a new tab. Does it look like something's missing? Sure enough, if we open the uMatrix pop-up interface again, we see youtube-nocookie.com (or just youtube.com) in the resource list which should tell you that there must be a YouTube video in that post that is being blocked. It also tells you exactly what was blocked, in this case a single frame:

If uMatrix is hiding the subdomains and you don't see www.youtube-nocookie.com, click this little thing in the 'all' row and it will expand the list of domains:

In the screenshots above you can see we are operating in the local scope (12bytes.org). You will notice that i allowed all requests for the 1st party domain, 12bytes.org, because it's my site and i trust it. You need not do the same and, as a rule of thumb, you should not do the same, nor is it required to get the video to play, at least not on 12bytes.org.

So we want to get that YouTube video working, but do we want to allow embedded YouTube videos for 12bytes.org only, or for all websites? This is what you need to be thinking any time you create filter rules. Since you probably want to allow YouTube videos for all websites, we need to switch uMatrix to the global scope and unblock the blocked frame for either the youtube-nocookie.com domain or the www.youtube-nocookie.com domain. Which you choose depends on whether you want to allow the resource for the root domain, including any sub-domain, or only the sub-domain. In this instance i suggest keeping it simple and allowing the frame for the root domain and all subdomains as shown. Make sure you save the change:

Now when we refresh that page, we might expect to see that YouTube video, but we don't. Opening the uM pop-up again and switching to the global scope, we discover that allowing the frame for youtube-nocookie.com caused more stuff to show up, this time a script for www.youtube-nocookie.com as well as another for a new domain, ytimg.com:

Making sure your are working in the global scope, let's unblock scripts for ytimg.com and youtube-nocookie.com. Make sure to save your changes:

Now when you reload the post page, everything should look good. We see the video frame and a nice image. Great. Click the play button and... nothing! Open the uM pop-up once more and we find that we need to allow XHR for the youtube-nocookie.com domain. You know what to do, so go ahead and make the change, making sure you're working in the global scope and remembering to save your change afterwards. Refresh the page again and click the play button on the video. It still doesn't work! Again, open the uM pop-up and you'll see another new domain has appeared, this time googlevideo.com (in case you didn't know, Google owns YouTube). If googlevideo.com is not displayed in the list, hold your Shift button when clicking the reload icon on the uM toolbar in order to force a full page reload and bypass the browser cache. Having to do this is typical when dealing with frames. Again, make sure you're working in the global scope and unblock the XHR requests for googlevideo.com and save your changes:

Now refresh the page one last time and the video should play. If it does not, you probably messed something up and there's a fair chance it's because you made one or more changes in the wrong scope and tried to correct them. If you messed something up, open the uM Dashboard, click the 'My rules' tab and in the 'Temporary rules' pane, delete all of the rules you created related to YouTube videos and 12bytes.org, but be careful not to delete the default rules or the global rules we set up originally. To do this, select the rules and press your delete key, then click the 'Save' and 'Commit' buttons:

Once you've deleted those rules and committed the changes to the 'Permanent rules' list, go back to the first step and try again.

De-borking other websites is generally not as time consuming as it was to get embedded YouTube videos to play and is instead usually accomplished with a couple mouse clicks and a page refresh verses a page reload. Just remember to turn to uMatrix first when a website isn't working as expected. If uM is blocking something it will let you know by displaying a badge on the toolbar icon. uBlock Origin will do the same, but it won't usually be the cause of the problem since we offloaded its dynamic filtering to uMatrix by not enabling its advanced mode of operation. Again, make sure you read the uMatrix wiki.

Another way to get a website working quickly is to check if there any user created rule recipes available for the site you're visiting or the resource it wants to load. If there are, that little puzzle-piece icon on the uM pop-up interface will become active and from it you can click a rule-set to import. Make sure you set uM to operate in the scope you want before importing the rule-set and then save the changes if you wish to make them permanent. Also be aware that user created rule-sets may allow more than you want to allow, however you can always adjust as necessary before saving the changes. User rule-sets can be helpful in determining why a site does not function properly. By the way, you could have done this for YouTube videos on 12bytes.org instead of letting me drag you through the mud, but it's important that you understand how uMatrix works and how to work with it.

Lastly i want to stress the importance of both the uBlock Origin logger and the uMatrix logger which are invaluable tools for troubleshooting tougher problems. You can get a better understanding of the uM logger by reading the documentation for the uBO logger since it is far more complete as of this writing, though some information is uBO specific.

THE END (lie)

While there are many more things you could do if you're really concerned about protecting your privacy and browser integrity, i hope this guide has been of some use to the technically adept novice or intermediate web surfer at which it is aimed. I welcome any questions or comments you may have, just please leave them in the comment section so others can benefit (you need not be logged in).

Lastly i want to again thank all of the dedicated and skilled people who created, maintain and contribute to the ghacks-user.js repository, especially Thorin-Oakenpants (aka, 'pants') and earthlng. This guide would never have been as comprehensive as it is without the benefit of that bunch of misfits :) Also i'd like to thank the many people who make privacytoolsIO possible. Their website is an excellent resource for those looking to protect their privacy and security.

IMPORTANT: If you incorporate suggestions made in this guide, please subscribe to the Firefox category on the subscription page. This article is updated fairly often and it's the best way to stay informed.

Resources

Further reading on this website

The 'ghacks' repository on GitHub

Everything else

Revision history

Click to expand...

custom Scroll to the bottom to see the latest changes.

11-APR-2015

  • first publishing

14-APR-2015

  • removed all Shim Storage add-on information since this functionality is duplicated in HTTP UserAgent cleaner.
  • almost all of the documentation for HTTP UserAgent cleaner was heavily revised.
  • various other edits and corrections.

15-APR-2015

  • updated user.js file
  • several other small updates and a few corrections

16-APR-2015

  • updated user.js file
  • switched uBlock versions since a new fork was created
  • updated uBlock images and documentation
  • added a "Current notices" section
  • misc. other corrections/updates/edits

17-APR-2015

  • updated and added more information for uBlock
  • updated one HTTP UserAgent cleaner screen-shot
  • misc. other corrections/updates/edits

18-APR-2015

  • updated HTTP UserAgent cleaner information
  • for HTTP UserAgent cleaner settings, the suggested settings were split into Suggested global setting for casual browsing and Suggested global setting for best protection.

22-APR-2015

  • updated information for HTTP UserAgent cleaner
  • updated user.js file
  • minor updates to uBlock information
  • misc. other minor changes

23-APR-2015

  • updated some HTTP UserAgent cleaner information
  • deleted information for 2 bugs regarding the X-Forward-For setting for HTTP UserAgent cleaner since they were not bugs
  • misc. other minor changes

25-APR-2015

  • updated information for HTTP UserAgent cleaner, including adding descriptions for the newly added features, Canvas and Fonts on the HTTP tab
  • updated the user.js file
  • updated some definitions of terms used in this document
  • added some more resources

26-APR-2015

  • updated the information for the Fonts filter on the HTTP tab of HTTP UserAgent cleaner

2-MAY-2015

  • updated HTTP UserAgent cleaner information to match changes in version 0.7.4.11a

3-MAY-2015

  • added Pure URL as a suggested add-on
  • updated contents of the user.js file
  • added and edited some information for HTTP UserAgent cleaner
  • added more resources in the References section

5-MAY-2015

  • updated list of recommended filters for uBlock
  • updated user.js file contents

13-MAY-2015

  • updated user.js file contents
  • updated a few settings recommendations for HTTP UserAgent cleaner

14-MAY-2015

  • minor updates to user.js file contents

17-MAY-2015

  • added information for securing DNS traffic
  • misc. minor updates

5-JUN-2015

  • switched to Raymond Hill's version of uBlock
  • updated uBlock filter information
  • added Fetch information for new version of HTTP UserAgent cleaner
  • updated user.js file contents
  • misc. minor updates

25-JUN-2015

  • updated uBlock settings to match the current development version (0.9.9.2)
  • misc. minor updates

8-JUL-2015

  • removed HTTP UserAgent cleaner since it is no longer being developed
  • removed Self Destructing Cookies add-on since its functionality can be handled by uMatrix
  • added uMatrix

9-JUL-2015

  • added more info for uMatrix and IP Config test results
  • updated user.js file contents
  • various other edits

13-JUL-2015

  • Minor edits for uMatrix usage text

20-AUG-2015

  • updated user.js file
  • removed pcxFirefox as a suggested 3rd party build since i had display corruption issues with it

5-FEB-2016

  • updated user.js file contents

12-FEB-2016

  • updated user.js file contents

29-APR-2016

  • updated guide information
  • updated user.js file and added a revision history to the file

1-MAY-2016

  • updated user.js file

12-MAY-2016

  • updated user.js file
  • minor grammar/spelling corrections

3-JUN-2016

  • corrected an error with pref 'layout.css.devPixelsPerPx' where the value was an integer instead of a string - this caused all prefs following it to be ignored

17-JUN-2016

  • set 'browser.fixup.hide_user_pass' back to its default value
  • added 'network.http.redirection-limit'

23-JUN-2016

  • added some basic information for configuring the Clean Links add-on

1-JUL-2016

  • corrected 'plugin.scan.*' values to be strings
  • added bogus preferences in the user.js file at the end of each section for troubleshooting potential loading problems

3-JUL-2016

  • changed the name of the troubleshooting/bogus preference to 12bytes.org-user-js-settings and added values to indicate the point at which the file stopped loading - a huge thanks to commenter 'Pants' for suggesting the troubleshooting preference and also for suggesting a far better way of implementing it than what i had done (by the way, 'Pants' is the author of the user.js config file used in the 'ghacks' article, A comprehensive list of Firefox privacy and security settings by Martin Brinkmann, so i'm very glad to have his input here)

16-SEP-2016

  • removed duplicate preferences in use.js file (see change-log in the file for details)

28-SEP-2016

  • removed Extension Defender from the list of recommended add-ons since it's home page is gone and the code hasn't been updated in two years
  • updated user.js file

18-FEB-2017

  • switched to using Pants' config v0.11 and mostly just appending my settings to the end of his - because this is a major update, no history of changes to individual preferences will be published

19-FEB-2017

  • published my user.js on GitHub which was forked from Pants' code
  • removed my user.js code from this page and linked to it on the GitHub page instead
  • changed my versioning scheme to match Pants' where the user.js version coincides with the version of Firefox it was developed for, so v51r1 would equate to version 51.x of Firefox and the r1 signifies the revision, in this case the first revision
  • updated user.js to include v51 of Pants' config - no preference changes so far as i know, just added/removed/changed comments
  • updated text in user.js section to account for the new changes
  • changes to comments and troubleshooting preference names and values, other minor changes

20-FEB-2017

  • updated user.js to version 51r2 - see the GitHub page for the change-log
  • updated info here regarding the user custom preferences section of user.js

12-MAR-2017

  • deleted the GitHub repository which i forked from Pants' 'ghacks' repository and created a new repository which does not include his code
  • some changes to user.js
  • some major editing of this document mostly in regard to the creation and changes of the GitHub repositories

17-SEP-2017

  • rewrote and updated much of the content pertaining to uMatrix
  • added section "Removing system add-ons"
  • added section "Sanitizing the default search engine plugins"

11-DEC-2017

  • added some add-ons to the recommended section
  • misc. minor edits

22-SEP-2017

  • i didn't keep track of all the changes and many were made - you'll have to re-read the guide :)

27-SEP-2017

  • added section "A special note about cryptocurrency miners"

30-SEP-2017

  • added more info about IndexDB storage in the "Terminology" and "uMatrix configuration" sections.

11-DEC-2017

  • added to the list of recommended add-ons
  • updated some content to reflect the current state of Firefox and WebExtensions
  • misc. minor edits

19-DEC-2017

  • added a link to my post about the Firefox add-on, Looking Glass
  • misc. minor edits

2-MAR-2018

  • minor edits

24-OCT-2018

  • removed cryptocurrency miner section
  • removed information about the OpenH264 Video Codec plug-in since it seems Firefox is no longer shipping it, at least not on Linux
  • removed the Load from Cache add-on
  • removed some information about uMatrix since uBlock Origin covers most everything uMatrix does and is better suited for removing advertisements, plus it's a much more active project.
  • updated some information
  • note that many more updates will occur in the next days, so i would suggest waiting until they are published before following this guide

25-OCT-2018

  • rewrote most of this guide, so if you read it before, read it again :)

26-OCT-2018

  • added the section 'Firefox profile in RAM'
  • misc. other minor edits

27-OCT-2018

  • lots of clarifications and polishing, added several resources

30-OCT-2018

  • added uMatrix to the add-on pile again
  • added the uMatrix sections of this document
  • removed info about running uBlock in advanced mode since we're using uMatrix for dynamic filtering instead
  • several minor edits
  • polishing

31-OCT-2018

  • add Cookie AutoDelete as a highly recommended add-on and updated configuration information for uMatrix to allow 1st party cookies by default
  • removed information about the Forget Me Not add-on
  • added information about First Party Isolation
  • added rule to uM to prevent web workers
  • added information about the uBO and uM logging functions
  • corrected some mistakes
  • polishing

2-NOV-2018

  • added info about using the user created rule sets for uMatrix, as well correcting some mistakes and clarifying other uM info
  • polishing

27-Nov-2018

  • added info about HSTS tracking
  • minor edits

30-Nov-2018

  • added more info to the uMatrix section, particularly about indexedDB storage
  • minor edits

11-Dec-2018

  • clarified much information regarding the user.js files as well as other parts
  • added more info about browser fingerprinting
  • added more detail regarding system add-ons
  • added a user-overrides.js template
  • updated Header Editor rules download
  • added several more 3rd party resources
  • misc. minor edits

21-Dec-2108

  • added POOP as a required add-on and accompanying configuration information
  • configuration information for Neat URL was located in the wrong section
  • minor polishing

22-Dec-2018

  • minor clarifications

26-Dec-2018

  • add notice about newsletter subscribing
  • corrected advice regarding spoofing the referrer which was suggested for both POOP and uM (now it's enabled in uM only)
  • dumped Cookie AutoDelete add-on - not needed when using uM and First Party Isolation, nor are any of these storage cleaning add-ons able to delete IndexedDB storage due to a shortcoming in the WebExt API, which is another reason to enable FPI
  • removed privacy.firstparty.isolate = false in user-overrides.js in order to enable First Party Isolation
  • added Restrict to Domain add-on to toggle privacy.firstparty.isolate (FPI) via toolbar button
  • removed the list of optional add-ons (NoScript and Smart Referrer)
  • minor edits
  • coming up: looks like i may be recommending to disable FPI in the very near future and use the Temporary Containers add-on instead - i'm playing with it now

29-Dec-2018

  • added some more info regarding HSTS tracking and the SiteSecurityServiceState.txt file based on user feedback - it appears some AV's might have a problem if this file is set to read only
  • added a new resources section specific to the 'ghacks-user.js' GitHub repo
  • added Temporary Containers (TC) add-on and associated info - this results in several major changes throughout the guide
  • added Firefox Multi-Account Containers add-on and associated info - this is used in conjunction with the TC add-on
  • added 'Using containers' section
  • removed Canvas Blocker add-on - not needed with TC
  • removed Restrict to Domain add-on - not needed with TC
  • removed Don't touch my tabs! add-on - (probably) not needed with TC
  • removed Header Editor - not needed for what we were using it for since the function is handled by TC
  • re-added privacy.firstparty.isolate = false to user-overrides.js
  • edited some uMatrix info regarding its privacy settings to reflect changes as a result of the TC add-on
  • added more info about importing rule-sets for uMatrix
  • moved Smart HTTPS add-on to the required section
  • moved Skip Redirect add-on to the required section
  • removed the suggested add-ons section
  • corrected mistakes and updated info in the section regarding integrity checking of the user.js/user-overrides.js files
  • reworked and updated the entire user-overrides.js file
  • removed mention of the template user-overrides.js file and associated download link - user should use the one provided in my GitLab repo
  • several minor edits/clarifications

3-Jan-2019

  • minor edit

12-Jan-2019

  • clarify information regarding the downloading of the configuration files thanks to a commenter
  • updated user-overrides.js
  • fix minor typo

17-Jan-2019

  • minor polishing

22-Jan-2019

  • updated info on HSTS tracking
  • updated info regarding downloading my user-overrides.js file

28-Feb-2019

  • added a link to a comment by 'Bushdoctor' who was kind enough to provide information about loading Firefox profiles in RAM for Windows users

29-Mar-2019

  • added instructions for cleaning user-overrides.js of obsolete preferences
  • minor edits

23-Apr-2019

  • removed info about manually cleaning the user-overrides.js file in favor of using the -c switch when running the updater.js/updater.bat script
  • added Site Bleacher to list of required add-ons
  • removed all info regarding containers as well as the Temporary Containers and Firefox Multi-Account Containers add-ons - i prefer to enable privacy.firstparty.isolate (the default in the 'ghacks' user.js) in combination with Site Bleacher (far less headaches)
  • replaced Neat URL with ClearURLs - while the former is a good extension, i think the latter is even better
  • replaced Smart HTTPS with HTTPZ
  • moved all add-on settings info to the required add-ons section
  • uBlock: added info for globally blocking 3rd party fonts while allowing 1st party fonts
  • misc. edits

24-Apr-2019

  • several clarifications and minor edits

1-May-2019

  • minor edits

6-May-2019

  • minor edits

7-May-2019

17-May-2019

  • removed mention of LibreFox (project is currently stalled due to legal nonsense)
  • minor corrections, clarifications and edits

21-May-2019

  • moved my Mozilla rant to a separate page
  • added a cryptominer block filter URL to uBlock

23-May-2019

  • added a note about enabling the search bar on the navigation bar
  • minor edits

27-May-2019

  • added note that this guide is not intended to be use with the Tor browser
  • minor edits

8-Jun-2019

  • very minor edit

13-Jun-2019

  • updated setup instructions for HTTPZ
  • minor edits

18-Oct-2019

  • moved my user-overrides.js from GitLab to Codeberg code repository

6-Nov-2019

  • stuck the uBlock config stuff on its own page

18-Nov-2019

  • added a note to Canvas Blocker marking it as optional
  • added a note regarding the no-workers: * true setting in uMatrix

29-Nov-2019

  • minor edit

13-Jan-2020

  • updated info for CanvasBlocker

23-Jan-2020

  • minor edits

7-Feb-2020

  • added ETag Stoppa
  • added more info regarding browser fingerprinting

18-Feb-2020

  • minor edits to uBlock, uMatrix and HTTPZ settings

10-Mar-2020

  • minor updates/clarifications

21-Mar-2020

  • removed ETag Stoppa since eTag filtering is now handled by ClearURLs
  • added detail regarding ClearURLs settings

5-Apr-2020

  • swapped out Decentraleyes for LocalCDN - thanks to commenter 'theltalpha' for reminding me about this

Malware - It's worse than you think

Relying on anti-virus software to protect your system is paramount to relying on guard rails to keep your car on the road. Here's why...

UPDATE: Since writing this article i have finally dropped Windows and moved to Linux-based operating systems which are inherently more secure in some ways (not all). I humbly suggest you consider doing the same.

My view on the subject of anti-malware/security suite software may be quite different than that of most casual computer users. I think that one of the primary keys to securing your system is a lack of stupidity rather than anti-virus software, and that relying on such products for protection is tantamount to relying on guard rails to keep your car on the road.

Fact number one: The primary method vendors of anti-virus software employ to protect against malware is by way of virus signatures, also known as 'definitions'. In order to develop a signature for a piece of malicious code, generally the vendor must be aware of its existence and since black-hat malware authors or those identifying 0-day vulnerabilities often sell their code or findings to major corporations, governments and other black-hats, they are obviously going to try to protect their secret as long as possible. This means that an exploit may exist undetected in the wild for hours, days, weeks or even years.

Fact number two: There are many viruses and software exploits that were never, are not currently, and may never be detected by any widely available, general anti-malware product. In fact, it is rather trivial to write a piece of malware that most popular anti-malware products will happily report as being 'clean'.

Fact number three: No single product can possibly protect your system against all threats, much less malware which is tailored for a specific target. On the other hand it simply is not feasible, or even possible in some cases, to run multiple anti-virus products simultaneously.

Fact number four: Everyone with an internet connection has very likely been infected with malware. If you think you are an exception, then i would posit that you simply never knew your system was/is compromised.

Fact number five: The good ol' days of malware are gone. While it was often humorous to read about or even experience your mouse cursor moving and combine that with the fact that you weren't the one moving it, much of the malware being distributed today is orders of magnitude more sophisticated. Today's malware is often designed to be as stealthy, efficient and resource friendly as possible so that it can remain completely undetected. With many millions of dollars to be earned in the malware market, the stakes are extremely high.

I'm not suggesting you throw your hands up in utter defeat, trash your anti-virus software and commence to having digi-sex without a digi-condom, but i want to make it clear that relying primarily upon anti-virus software to protect you against malware threats is a road laden with land mines, regardless of how many products you use, what they cost, what they scored on the latest Virus Bulletin test, or what bells and whistles the vendor claims it has. If there was just one, affordable anti-virus product that protected against even the majority of the threats, there wouldn't be heaps of malicious hackers getting paid to write malware any longer, yet malware is more prevalent today than ever before and more people are running anti-malware software today than ever before. What does that tell you about the overall effectiveness of the anti-virus industry? And it gets worse.

The 2016 article, Antivirus software could make your company more vulnerable, from CSO Online, points out exactly what is suggested in its title which is that using popular anti-malware products that are generally trusted can, in and of itself, get you in trouble:

Since June, researchers have found and reported several dozen serious flaws in antivirus products from vendors such as Kaspersky Lab, ESET, Avast, AVG Technologies, Intel Security (formerly McAfee) and Malwarebytes. Many of those vulnerabilities would have allowed attackers to remotely execute malicious code on computers, to abuse the functionality of the antivirus products themselves, to gain higher privileges on compromised systems and even to defeat the anti-exploitation defenses of third-party applications.

Exploiting some of those vulnerabilities required no user interaction and could have allowed the creation of computer worms -- self-propagating malware programs. In many cases, attackers would have only needed to send specially crafted email messages to potential victims, to inject malicious code into legitimate websites visited by them, or to plug in USB drives with malformed files into their computers.

This does not mean you can't protect yourself from the majority of common threats however. Not only can you do so, but you can do so quite effectively without even using an anti-virus product. I wouldn't recommend that Windows users go without any protection, but my point is that anti-virus software plays a much less significant role for the savvy computer user who relies on more effective means of protection than any software product can provide.

Security is a dish best served cold. And in layers. Here are some of the key security practices i would suggest for most anyone, especially the casual computer user who is at the greatest risk due to their lack of technical knowledge:

  • Realize what the vectors for attack are, which is basically anything you connect to your machine including flash drives, discs, modems, routers, printers, USB devices, T.V.'s and even peripherals like mice and keyboards, as well as anything that is delivered through your network connection.
  • Realize that malicious software isn't likely to be considered malicious by your anti-virus product until after it is known to exist and a signature has been developed and pushed out by the vendor, leaving you completely vulnerable in the interim. Also realize that the existence of some exploits and malware may never be known.
  • Realize that no anti-malware product on the planet is bullet-proof -- Not. Even. Close. -- and many are just plain garbage or are effectively malware themselves which vacuum up personal data and send it off to who knows where, or worse. Do some research before choosing a product.
  • By learning just a handful of good security practices, the burden of protection will naturally shift more toward the smarter you and away from your dumber anti-virus software.
  • Do not install crap-ware or software from nefarious sources and, by all means, forget about "warez" and "cracks" as failing to do so will cause doom at some point.
  • That game or joke document that's being passed around all over Facebook or by email or wherever? Let it pass.
  • Get in the habit of never opening email attachments. None. Ever. Period. The only exception is if you are expecting something important from someone you trust and even then you should not trust any attachment blindly, especially if it's an executable. Even hyperlinks can be dangerous. Your coworker or close friend could be using a little social engineering to infect you, or they could be infected themselves and not know it, or it might not be your coworker or friend at all, but rather someone impersonating them. If someone sends you something you really want to see, ask them to send a link to the webpage if possible and make sure you know where that link is pointing before clicking it (and ask them to quit sending attachments unnecessarily).
  • For many of us, our internet browser is are our primary window to the digital world. It is also a most attractive vector for attack, not only because of security holes and poorly coded extensions, but because of what websites people visit. Tighten down the security of your web browser and remove any unnecessary plugins, including Flash, Java, the Adobe PDF viewer, etc.. Most modern browsers can handle video and PDF content without plugins anyway and Java is rarely used by websites anymore.
  • Browse smart and stay away from porn sites or any other questionable sites, even if they are hugely popular. Keep in mind that you need not click or do anything on a malicious website to become infected other than simply visit it (see drive-by malware). I would also suggest dumping Microsoft Internet Explorer and replacing it with something more secure and transparent, which is basically anything other than IE.
  • As with your browser, your email client is also a huge vector for attack, so learn how to harden it by disabling JavaScript and HTML mail. As with your browser, i would suggest dumping any Microsoft email clients and replacing them with something more secure and transparent, such as Thunderbird.
  • Scan everything you download from any source with a decent anti-virus product. You don't have to run a bloated "security suite" in the background that analyzes your every click and key press and file you open as long as you work and play smart, but at least have an on-demand scanner available to manually scan all incoming downloads and email attachments.
  • If you're not sure about the integrity of a piece of software or the reputation of a website, scan it using something like the VirusTotal service, which uses a whole bunch anti-malware products to scan a single file or website URL. There are several add-ons for Firefox that make accessing VirusTotal very easy. Certainly do not rely on the over-pimped "Web of Trust" service or any other service where the data comes primarily from everyday users who lack knowledge regarding malware and rate sites based primarily upon their bias.
  • If you use only popular, mainstream software products for protection, such as Windows Defender or the Comodo Internet Security suite, etc., realize that chances may be significantly higher that malware is in play which is purposely designed to completely bypass the protection these popular products offer. The larger the following, the bigger the target.
  • Do not log on to your operating system as an administrator.
  • Keep regular backups of your data, preferably off site and encrypted, but at least on an external drive. If you have become infected, do not rely on the Windows System Restore utility since the malware may have infected those backups as well.
  • If you discover a virus, and especially if it's a Trojan, assume all your data has been compromised including any passwords, banking information, credit card numbers, documents, etc.. You should immediately unplug your computer from your modem and take action to remove the virus, change all of your passwords and notify your bank.

Again, i do not advocate running around the web with your skirts flying high and no underwear on. The trick is to find a good anti-malware product and, while there are hoards of products to choose from, there are not that many that are actually worth considering. In the past i have had extended communications with a couple of people who are apparently heavy hitters in the anti-malware industry and Bitdefender seems to be one of the better general purpose products. So is Malwarebytes Anti-Malware. I will emphasize again however that there is no single product, nor combination of products, that will protect you from all threats.

Personally i don't run a resident virus scanner at all any more, but i do use the Emsisoft Commandline Scanner which is an on-demand scanner (you have to run it manually) to scan everything i download. It is a general purpose anti-malware tool that is probably about as good as they come and it's free for personal use. Also known by it's executable, a2cmd, the Emsisoft scanner is a hybrid of both the Emsisoft and Bitdefender products.

While i have been infected a couple of times back in the day, to my knowledge i haven't been infected with any malicious software in the last 15 years or so since i started learning more about computer security. I am very careful about what i download and install, what websites i visit and where i allow JavaScript or browser plugins to run and what email attachments i choose to open. I have taken measures to harden my browser and email client and i use a non-Microsoft firewall and anti-virus products. I never plug anything into my everyday machine that i don't own, especially flash memory. Still, i feel very threatened by the potential that something will slip by my defenses, but my paranoia plays a key role in keeping me infection free... at least to the best of my knowledge.

Good luck. You'll need it.

Encrypting DNS Traffic (and why you want to)

Prevent your ISP and others from collecting information about what websites you visit by encrypting your DNS traffic.

UPDATE (25-Jan-2020): This article is largely obsolete but i'm keeping the page alive because i intend to rewrite it at some point. One of the items i want to add is how to set up DNS over TLS on your network router so that all devices that connect to your network can benefit from private and encrypted DNS resolving.

UPDATE (26-Jan-2018): If you use a Virtual Private Network (VPN) you do not necessarily need to worry about encrypting your DNS traffic as long as a), your VPN offers a DNS service and b), you trust them. The other primary advantage of using a VPN is that, like Tor, all of your internet traffic between you and the VPN exit node is encrypted, meaning neither your ISP nor anyone else should be capable of monitoring it. Yes, a VPN is yet another expense and as much as i dislike paying more to access the web on top of what my ISP charges, it doesn't cost much and i can't see myself ever going back to not using one.

The problem...

DNS -- Domain Name System -- is the service responsible for converting a domain name, such as '12bytes.org', to an IP address that is understood by computers routing internet traffic. The DNS server(s) that you are currently accessing to convert domains to IP addresses are configured in the properties of your network adapter, each adapter having its own DNS configuration, or perhaps your router or modem.

DNS is a weak link in the internet chain because this traffic is most often unencrypted and open to man-in-the-middle (MITM) attacks, even when visiting an encrypted (https) website. An attacker can easily set up their own DNS server and, using a little social engineering and/or malware, convince you to change your current DNS server, or change it without your knowledge, to the one controlled by the attacker. One possible result is that you could visit 'your-bank.com' but actually land on a forged website that may look exactly like the authentic one and thus there would be no cause for alarm while you log on with your user name and password, which would then be in the hands of the attacker. I am quite sure the tactic of DNS spoofing is used by law enforcement as well.

Lastly, i wrote this tutorial while using Windows and have since switched to Linux. A tutorial for the Debian flavors of Linux can be found here.

The solution...

Securing your DNS traffic is easy using DNSCrypt (don't download the client from the OpenDNS page). If you're not afraid of the command-line and wish to keep the process as efficient as possible, i would suggest reading the article How to Encrypt Your DNS for More Secure Browsing by How-To Geek. If you prefer a point-and-click approach however, along with a nice GUI for controlling DNSCrypt and selecting your DNS server, here's how to install and configure Simple DNSCrypt:

If you have another version of DNSCrypt installed, uninstall it first. If there is no uninstaller, then run the following command:

dnscrypt-proxy --uninstall

Next, download Simple DNSCrypt from the authors site and install the .msi package. The GUI to configure the DNSCrypt client should start automatically after the installation is complete. Configuring the DNSCrypt client is easy:

  1. Enable DNSCrypt for your network adapter.
  2. Select a DNS service.
  3. Enable the Primary DNSCrypt Service. If the service does not start, try disabling DNSCrypt for your adapter and then enabling the service. Note that the Secondary Resolver settings are disabled because this feature is not completely implemented at the time of this writing.
  4. In the 'Advanced Settings' you can download a fresh copy of the DNS resolvers list and by clicking the 'Plugins' button you can disable IPV6.
  5. Open port 443 in your firewall to allow outgoing UDP traffic for dnscrypt-proxy.exe if you need to.
  6. If you installed the 'dnscrypt-proxy' service, you can exit the Simple DNSCrypt GUI, otherwise it will need to be left running.
Simple DNSCrypt configuration for Windows

Verify DNSCrypt is working...

Windows 7 Network Connection Dialogs
Windows 7 network connection settings

To verify that everything is working, check the properties for your network adapter and make sure the primary DNS server is set to 127.0.0.1 and that the secondary server is empty as seen in the screen-shot. If it is not, make it so. Next, try visiting a website to make sure everything is working.

If necessary, reboot your machine or flush the Windows DNS cache by opening a command prompt and entering: ipconfig /flushdns, then load a web page to ensure DNSCrypt is working.

If you're wondering about the default Windows 'DNS Client' service, leave it running. You can also leave in place any firewall rules for DNS look-ups on port 53 to enable easy switching of the DNS servers in your network adapter for troubleshooting purposes.

At this point i'm not entirely sure what happens with DNS caching, but it appears that a query is sent with every request, which is not optimal. I hope to write more about this after i figure out exactly what is happening in this regard.

Tech

Cool Android Apps

A handful of cool and useful free, mostly open source Android apps...

I like to fool around with my electronic devices to learn about them and my Android powered smartphones are always victims of my curiosity. Upon entering the smartphone world, i soon found myself installing custom ROMs, tweaking various things and looking for apps to replace the functionality of all of the Google apps which i remove (i hate Google for a number of reasons).

Since neither the Google Play Store nor the Google Services Framework exist on my devices, i began looking for alternative repositories and i quickly discovered F-Droid which is a great resource for (mostly) free, open source, ad-free Android apps that are compiled from source by the F-Droid team. Compiling from source is important because it guarantees that the compiled app contains nothing more than what is in the publicly available source code.

Before you get started installing apps from F-Droid you will need to enable the installation of apps from unknown sources if you haven't already done so. I'm sure some might see this as a major no-no, to which i would reply that, out of 27 repositories tested in a 2017 independent study, including the Google Play Store, F-Droid was the only one in which no instances of malware were found. While the number of instances of malware in the Play Store was low, understand that the privacy aspect of those apps was not considered and this is perhaps the greatest concern with Play Store apps. Also see:

If you still have concerns about using the F-Droid app repository, i suggest reading Android Markets: How safe are alternative sources?.

F-Droid does not require you to create an account to access their repository and once the F-Droid client app is installed, which makes it super easy to browse their repo, it will notify you when an update is available for any app which was installed using it. The selection of apps isn't exactly massive at the moment but it is probably adequate for most people and it is constantly growing. They also have an active community forum where members can suggest new apps. Other places to look for apps are GitHub, XDA Developers, AndroidCentral and the Google developers websites.

Following are some of my favorite apps for Android devices. Keep in mind that if you download these apps without using the F-Droid client, you may not be made aware of updates. It is therefore recommended to install the F-Droid client app first and install your apps using it.

F-DroidThe F-Droid client app provides easy device access to the F-Droid repositories for open source Android apps. Unless you want to install the compiled apk files directly, which i don't recommend because you will not be informed of updates, you will need the F-Droid client. F-Droid @ F-Droid.

 

AdAway AdAway is a compact and effective ad blocker which uses less resources than AdBlock+ because it leverages the hosts file, however this requires you have root privileges. Updating the host file can be done manually or automatically. AdAway @ F-Droid.

 

AFWall+AFWall+ provides a GUI to easily manipulate the Linux iptables firewall. AFWall+ comes packaged with the iptables and BusyBox binaries and requires root privileges to run. Note that there is a donate version which unlocks a few extra features, such as logging. If you don't wish to get the donate key at the Google Play Store, contact the AFWall+ developer to see what options he may offer. AFWall+ @ F-Droid.

 

Amaze file browserAmaze is a really nice file manager with an intuitive and attractive interface. It includes an FTP server which allows you to browse the file system over your network. Root privileges will be required if you want to browse the entire file system. Amaze is pretty powerful, but If you need something even more powerful, try Ghost Commander below. Amaze @ F-Droid.

 

Barcode ScannerBarcode Scanner supports many barcode types as well as QR codes and it seems to be pretty good at what it does. Barcode Scanner @ F-Droid.

 

BubbleBubble is a simple, handy app for leveling things and measuring angles in different ways. It is old no longer maintained and can be a bit buggy, but it's the best app of its type i could find on F-Droid and it works well enough. Bubble @ F-Droid.

 

Simple CalendarCalendar is part of a suite of open source apps by Simple Mobile Tools. Calendar works offline without having to share your data with a 3rd party. It provides what you would expect from a typical calendar app and does so in a visually pleasing way. There are plenty of settings to customize the interface to your liking. Simple Calendar @ F-Droid.

 

Call RecorderCall Recorder simply records both incoming and outgoing calls and offers several options for doing so, though an option to selectively record calls via a simple choice when a call is placed or received is not one of them unfortunately. The developer tells us that most phones will not support call recording, so don't blame Call Recorder if it bombs. I would also venture a guess that it may not work on devices that are running an OEM version of Android. Call Recorder @ F-Droid.

 

DrawDraw is part of a suite of open source apps by Simple Mobile Tools. Draw is a bare-bones app that lets you draw stuff. I find it useful when i have a spur of the moment design idea and no paper. Draw @ F-Droid.

 

ForecastieForecastie is a simple weather forecast app that works off-line and pulls weather information from OpenWeatherMap. It provides a fairly detailed forecast in text form for the current day, as well as an extended forecast. Forecastie does not display a radar weather map, so if you want that functionality you might try wX below. Forecastie @ F-Droid.

 

Ghost CommanderGhost Commander is a powerful, feature packed and polished file manager for Android, however you will need root access to take full advantage of. It can be extended even further with plugins. If you don't need all the functionality that Ghost Commander provides, try Amaze above. Ghost Commander @ F-Droid.

 

KeePassDroidKeePassDroid is a great little password manager for storing all your passwords, log-on credentials or private text snippets. It is compatible with the KeePass Password Safe database files. One caveat that should be mentioned here is that the base-band OS (radio firmware) on all smartphones is proprietary and apparently has low-level access to the keyboard, so i wouldn't suggest storing any super important passwords on any device that has a cellular modem, Android or otherwise, especially if you are a journalist or activist. KeePassDroid @ F-Droid.

 

Music PlayerMusic Player is yet another open source app from Simple Mobile Tools. It has all the basic functionality you'd expect, including the ability to manage playlists. Like all of the Simple Mobile Tools apps, Music Player has a clean and pleasing interface that is easy to use. Music Player @ F-Droid.

 

Offline CalendarOffline Calendar is a companion for the default calendar app that allows it to work offline without having to rely upon a third party to store (spy on) your personal data, however since your calendar data is stored locally, no syncing is possible. Offline Calendar @ F-Droid.

 

Omni NotesOmni Notes is a really nice app for creating different kinds of notes, including checklists, text, image and audio notes. I use this app a lot for managing to-do lists. One nice feature it has that several others lack is the ability to re-order checklist items by drag-and-drop which is great if you want to sort stuff by priority. Omni Notes @ F-Droid.

 

Open CameraOpen Camera is a powerful, feature rich camera app for those that don't like the default camera. It supports front and rear cameras, image stabilization, manual controls, many different resolutions, auto-focus and much more. That said, the developer cannot possibly support every feature of every camera and so it may not be a good fit for some camera hardware. Open camera @ F-Droid.

 

OS MonitorOS Monitor is a handy app which allows you to monitor various aspects of the Android OS including network connections and running processes, as well as being able to view and export system logs. OS Monitor @ F-Droid.

 

OsmAndOsmAnd is a very powerful map and navigation application similar to Google Maps, however it uses Open Street Maps by default instead of the proprietary Google Maps, though it is capable of using maps from other sources. With all this power comes a ton of configuration options and it can be extended even further with plug-ins, so expect to fool around with it for a while in order to make efficient use of it. Its features include GPS voice guided navigation, GPS status, favorites, POI display, adding audio and video clips to locations and much more. It also works offline so you don't need a data connection to use it. There is both a free and donate version of OsmAnd and it appears that the version currently published on F-Droid is the fully featured one. OsmAnd @ F-Droid.

 

Privacy BrowserPrivacy Browser, as the name implies, is a privacy oriented web browser that is also focused on security. This slick browser makes it very easy to allow or disallow web storage, JavaScript and cookies on a per-site basis as well of many other options. Privacy Browser @ F-Droid.

 

Sensor ReadoutSensor Readout can access many of your devices sensors, some of which you may not know it had, and output the raw data in a scalable graph form. It's an interesting little app that may not have much use for most people, but i think the acceleration data could be useful to those who want to minimize vibration in machines like a multi-rotor aircraft or just about anything else that vibrates too much. Sensor Readout @ F-Droid.

 

UnitsUnits is a very powerful calculator and unit conversion app for converting from one unit of measure to another, such as from inches to centimeters. If you would rather something simpler, but still comprehensive, try Unit Converter Ultimate below. Units @ F-Droid.

 

Unit Converter UltimateUnit Converter Ultimate is another nice conversion app with lots of predefined conversion formats. Though it lacks a calculator and the powerful syntax of Units, it is still quite comprehensive. Unit Converter Ultimate @ F-Droid.

 

wXwX may be the most comprehensive (and complex) weather app for Android on this side of the Milky Way. Trust me when i tell you it is not for the faint of heart as there are so many screens, widgets and options (hundreds?) it's overwhelming. Although wX is obviously oriented toward very serious weather geeks (think meteorologists, storm chasers), i like it because it has the ability to display several kinds of animated radar maps and it doesn't spy on you. The developer seems like a great guy too. wX @ F-Droid.

 

Auroa Store Aurora Store is a Google Play Store alternative that can list, download, install and update apps from the Play Store without having to create a Play Store account. From the official description, "[...] using Aurora you can download apps, update existing apps, search for apps, get details about app tracker & adware and much more. You can also Spoof your Device Information, Language and Region to get access to the apps that are not yet available or restricted in your Country or Device.". You should probably only use this if, like me, you do not have the Play Store (GAPPS) installed and the app you want is not available on F-Droid and you realize the privacy and security risks of downloading apps from the Play Store. Aurora Store @ F-Droid.