firejail Firejail is a SUID security sandbox program that reduces the risk of security breaches by restricting the running environment of untrusted applications using Linux namespaces. It allows a process and all its descendants to have their own private view of the globally shared kernel resources, such as the network stack, process table, mount table. Firejail can sandbox any type of processes: servers, graphical applications, and even user login sessions. Written in C with virtually no dependencies, it should work on any Linux computer with a 3.x kernel version.