How to gain added security in Firefox with the site isolation feature, Fission

The Mozilla developers are doing everything they can to prevent Firefox from fading into the sunset, a browser forgotten and unused. That’s a good thing because Firefox is an important browser that has brought about game-changing features over the years. One thing (at least I hope) the developers are starting to see is that it’s more important to focus on releasing a browser that works reliably, efficiently and securely, rather than one bloated with features no one will use.

To that end, the Firefox developers have turned to browser security with a new feature, called Fission (also known as Site Isolation), that is long overdue.

What Site Isolation does is isolate each site into a separate process, which makes it harder for malicious websites to access private information such as passwords, credit card numbers, social security numbers and more, that has been loaded by other sites. With Fission, attackers won’t be able to use exploits (such as Spectre and Meltdown) to collect sensitive data from in-memory content.

This is an important feature, one that everyone should be using. Although the feature is still in the experimental phase, it can be enabled on all versions of Firefox: Release, Beta and Nightly.

I’m going to show you how to enable Fission on both the standard and Nightly release of Firefox.

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What you’ll need

To enable Fission, you’ll need an updated version of your Firefox release of choice.

How to enable Fission on Firefox

We’ll first look at the regular release of Firefox. To enable Fission, open Firefox and type about:config. In the resulting window type fission.autostart. When the option appears, double-click False until it says True (Figure A).

Figure A

Restart Firefox and Fission is now enabled.

How to enable Fission on Firefox Nightly

Now, let’s enable Fission on Firefox Nightly. This is somewhat easier. Open Firefox Nightly and type about:preferences#experimental in the address bar. Scroll down to Fission (Site Isolation) and check the associated box (Figure B).

Figure B

Restart Firefox Nightly to finish the enabling of Fission.

Hopefully, the Mozilla developers will make this new feature enabled, by default, for every version of Firefox. The need for browser security is at an all-time high. If Firefox could only add a workspaces feature, I could switch back to the open source browser as my daily driver.

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