Firejail is a SUID sandbox program that reduces the risk of security breaches by restricting the running environment of untrusted applications using Linux namespaces, seccomp-bpf and Linux capabilities. 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 work in a SELinux or AppArmor environment, and it is integrated with Linux Control Groups.

Written in C with virtually no dependencies, the software runs on any Linux computer with a 3.x kernel version or newer. It can sandbox any type of processes: servers, graphical applications, and even user login sessions. The software includes sandbox profiles for a number of more common Linux programs, such as Mozilla Firefox, Chromium, VLC, Transmission etc.

The sandbox is lightweight, the overhead is low. There are no complicated configuration files to edit, no socket connections open, no daemons running in the background. All security features are implemented directly in Linux kernel and available on any Linux computer. To start the sandbox, prefix your command with “firejail”:

$ firejail firefox            # starting Mozilla Firefox
$ firejail transmission-gtk   # starting Transmission BitTorrent 
$ firejail vlc                # starting VideoLAN Client
$ sudo firejail /etc/init.d/nginx start

Project webpage: https://firejail.wordpress.com/

Download and Installation: https://firejail.wordpress.com/download-2/

Features: https://firejail.wordpress.com/features-3/

Documentation: https://firejail.wordpress.com/documentation-2/

FAQ: https://firejail.wordpress.com/support/frequently-asked-questions/

Version 0.9.41~rc1 was released.

--user option was deprecated, please use "sudo -u username firejail application" instead.

Symlinks outside user home directories are allowed:

      --whitelist=dirname_or_filename
              Whitelist directory or file. This feature  is  implemented  only
              for  user  home, /dev, /media, /opt, /var, and /tmp directories.
              With the exception of user home, both the  link  and  the  real
              file should be in the same top directory.

              Example:
              $ firejail --noprofile --whitelist=~/.mozilla
              $ firejail --whitelist=/tmp/.X11-unix --whitelist=/dev/null
              $ firejail "--whitelist=/home/username/My Virtual Machines"

AppImage (http://appimage.org/) is a distribution-agnostic packaging format. The package is a regular ISO file containing all binaries, libraries and resources necessary for the program to run.

We introduce in this release support for sandboxing AppImage applications. Example:

$ firejail --appimage krita-3.0-x86_64.appimage

All Firejail sandboxing options should be available. A private home directory:

$ firejail --appimage --private krita-3.0-x86_64.appimage

or some basic X11 sandboxing:

$ firejail --appimage --net=none --x11 krita-3.0-x86_64.appimage

Major software applications distributing AppImage packages:

• Krita: https://krita.org/download/krita-desktop/
• OpenShot: http://www.openshot.org/download/
• Scribus: https://www.scribus.net/downloads/unstable-branch/
• MuseScore: https://musescore.org/en/download

More packages build by AppImage developer Simon Peter: https://bintray.com/probono/AppImages

AppImage project home: https://github.com/probonopd/AppImageKit

AUDIT
       Audit feature allows the user to point out gaps in  security  profiles.
       The  implementation  replaces  the  program to be sandboxed with a test
       program. By default, we use faudit program distributed with Firejail. A
       custom test program can also be supplied by the user. Examples:

       Running the default audit program:
            $ firejail --audit transmission-gtk

       Running a custom audit program:
            $ firejail --audit=~/sandbox-test transmission-gtk

       In  the examples above, the sandbox configures transmission-gtk profile
       and starts the test program. The real program,  transmission-gtk,  will
       not be started.

       Limitations: audit feature is not implemented for --x11 commands.

       --noexec=dirname_or_filename
              Remount directory or file noexec, nodev and nosuid.

              Example:
              $ firejail --noexec=/tmp

              /etc and /var are noexec by default. If there are more than one
              mount operation on the path of the file  or  directory,  noexec
              should  be  applied to the last one. Always check if the change
              took effect inside the sandbox.

      --rmenv=name
              Remove environment variable in the new sandbox.

              Example:
              $ firejail --rmenv=DBUS_SESSION_BUS_ADDRESS

BitTorrent: deluge, qbittorrent, rtorrent, transmission-gtk, transmission-qt, uget-gtk

File transfer: filezilla

Media: vlc, mpv, gnome-mplayer, audacity, rhythmbox, spotify, xplayer, xviewer, eom

Office: evince, gthumb, fbreader, pix, atril, xreader,

Chat/messaging: qtox, gitter, pidgin

Games: warzone2100

Weather/climate: aweather

Astronomy: gpredict, stellarium

Browsers: Palemoon

Gitter, gThumb, mpv, Franz messenger, LibreOffice, pix, audacity, strings, xz, xzdec, gzip, cpio, less, Atom Beta, Atom, jitsi, eom