Mozilla to Bring Chrome-Like Site Isolation Feature for Firefox Users

Chrome offers an additional protection against some typical kind of threats, known as site isolation feature. This enables stronger safety nets and prevents untrustworthy websites to leak information to malicious sites.

Mozilla recently reported that they have also started work on a similar project. Not only this, the new project will also improve RAM usage for every content processing which in turn will help for the site isolation feature to work well. Mozilla is calling its site isolation feature as Project Fission and its RAM usage improvement will be known as Fission MemShrink. Project Fission which is similar to Chrome's Site Isolation helps to prevent attacks that might take place between processes and sites by restricting the sharing of multiple processes between sites. It was Google who rolled out Site isolation for Windows; macOS; Linux and Chrome OS users.

Websites are designed in a way that they cannot access each other's data inside the browser owing to code that enforces the Same Origin Policy. However, occasionally security bugs are found in this code and malicious websites may try to bypass these rules to attack other websites. Google Chrome team aims to fix such bugs as quickly as possible. The process of site Isolation offers a second line of defense to make such attacks less likely to succeed. This makes sure that different pages from various websites are always directed to different processes.  It will also make it possible to block the process from receiving certain types of sensitive data from other sites. As a result, a malicious website will find it more difficult to steal data from other sites, even if it can break some of the rules in its own process.

Bleeping Computer reported that they got hold of a Mozilla official email where they got to know about the beginning of Fission MemShrink – the project aimed at less memory usage in content processing. This will ensure up to 7MB of less memory usage throughout all platforms. In order for site isolation to function properly, it is required to be able to run at least a hundred content processes in an average session. Every process runs on its own base memory overhead - memory that is used just for creating the process no matter what is running in it. For the post-Fission world, that overhead needs to be less than ten MB per process in order to restrain the extra overhead from Fission below 1GB.

It was also reported by the mail that right now the best-cast platform, Windows 10 runs somewhere between 17 and 21MB. The same for Linux and OS-X oscillates between 25 and 35MB. On an average For an ordinary session, the range can be between 2 and 3.5GB. This simply means that in the best case it is required to reduce the memory use in content processes by at least 7MB. The problem, of course, is that there are only so many places where memory can be cut without losing functionality.

As mentioned, Mozilla does not guarantee whether it will succeed in reducing RAM usage, but the effort towards it has begun. As it's still a work in progress, there is no timeline for the launch of Project Fission.