Firejail


Firejail is a security sandbox tool designed to enhance the security of applications by isolating them in a sandbox environment. It is a free and open-source software available for Linux-based operating systems. Firejail was created by Antti Kantee and is maintained by a community of developers.

Implementation

Firejail keeps applications safely isolated by combining several built-in security features from the Linux kernel. When an application is launched through Firejail, it sets up a restricted environment for the process. In fact, the application runs in its own little bubble, with a limited view of the rest of the system; it can’t easily see or mess with file system, networks, or other resources outside that bubble. In the end, if an application gets hacked or starts acting up, the damage remains restricted and doesn’t spread across the whole computer.
Firejail applies additional kernel-level restrictions, such as filtering system calls and reducing privileges. System call filtering is like putting a gatekeeper on the application: it blocks the process from using certain kernel commands that it doesn’t need, which helps stop attackers from exploiting weak spots or unnecessary doors into the system. This multi-layered approach limits the system’s vulnerabilities and prevents sandboxed processes from performing actions outside their intended role.
The Firejail project is distributed under the GPL-2.0 open-source license, which anyone can use, modify, and share freely. Its official GitHub repository has hundreds of default sandbox profiles for common applications, making it easy to set them up securely without building everything from scratch.
The project keeps improving by adding Linux security tools like Landlock to make better isolation and minimize potential security risks for sandboxes. The repository is regularly updated with bug fixes and improvements, showing active community support. These practices ensure that Firejail remains up to date with the latest kernel features and security standards.

Features

  • Sandboxing: Firejail allows users to run applications in isolated environments, preventing them from accessing sensitive files and system resources.
  • SELinux Integration: It integrates with SELinux to provide robust security policies.
  • Resource Limitation: Firejail can limit the resources that a sandboxed application can use.
  • Network Isolation: It can restrict network access for sandboxed applications, enhancing security against network-based attacks.
  • Filesystem Access Control: Firejail provides fine-grained control over which files and directories an application can access.

    Usage

Firejail is typically used to run potentially untrusted applications or scripts in a controlled environment. It can be invoked directly from the command line or configured to run specific applications automatically.