Firejail is a lightweight SUID sandbox for Linux that restricts untrusted applications by isolating their access to system resources.
The tool addresses the risk of security breaches by leveraging Linux namespaces, seccomp-bpf filtering, and Linux capabilities to give sandboxed processes their own private view of kernel resources including the network stack, process table, and mount table. It requires minimal configuration—no daemons, no socket connections, no complex config files—and implements all security features directly in the kernel. Written in C with virtually no dependencies, it runs on any Linux system with a 3.x kernel or newer and can sandbox servers, graphical applications, and user login sessions. The project includes pre-built profiles for common applications like Firefox, Chromium, VLC, and Transmission.
Firejail suits developers and system administrators who need to run untrusted or potentially risky applications with minimal overhead. It works alongside SELinux or AppArmor and integrates with Linux Control Groups. The lightweight nature makes it practical for desktop users wanting to sandbox browsers or media players without noticeable performance impact. Anyone seeking a simple, kernel-based sandboxing approach without external dependencies or daemon processes will find this tool appropriate.
The project maintains active continuous integration across multiple platforms including GitHub Actions, GitLab CI, and Debian CI. Development activity shows ongoing attention to security with a dedicated security policy document. The tool is packaged in major Linux distributions and available through multiple installation channels including direct releases and distribution repositories.
