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.
 Firejail Intro |
 Firejail Demo |
 Debian Install |
 Arch Linux Install |
 Disable Network Access |
 Firejail Security Deep Dive |
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://github.com/netblue30/firejail/wiki/Frequently-Asked-Questions
Wiki: https://github.com/netblue30/firejail/wiki
GitLab-CI status: https://gitlab.com/Firejail/firejail_ci/pipelines/
Video Channel: https://www.youtube.com/channel/UCi5u-syndQYyOeV4NZ04hNA
Backup Video Channel: https://www.bitchute.com/profile/JSBsA1aoQVfW/
We take security bugs very seriously. If you believe you have found one, please report it by emailing us at netblue30@protonmail.com
Security Adivsory - Feb 8, 2021
Summary: A vulnerability resulting in root privilege escalation was discovered in
Firejail's OverlayFS code,
Versions affected: Firejail software versions starting with 0.9.30.
Long Term Support (LTS) Firejail branch is not affected by this bug.
Workaround: Disable overlayfs feature at runtime.
In a text editor open /etc/firejail/firejail.config file, and set "overlayfs" entry to "no".
$ grep overlayfs /etc/firejail/firejail.config
# Enable or disable overlayfs features, default enabled.
overlayfs no
Fix: The bug is fixed in Firejail version 0.9.64.4
GitHub commit: (file configure.ac)
https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b
Credit: Security researcher Roman Fiedler analyzed the code and discovered the vulnerability.
Functional PoC exploit code was provided to Firejail development team.
A description of the problem is here on Roman's blog:
https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt
https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/
Try installing Firejail from your system packages first. Firejail is included in Alpine, ALT Linux, Arch, Chakra, Debian, Deepin, Devuan, Fedora, Gentoo, Manjaro, Mint, NixOS, Parabola, Parrot, PCLinuxOS, ROSA, Solus, Slackware/SlackBuilds, Trisquel, Ubuntu, Void and possibly others.
The firejail 0.9.52-LTS version is deprecated. On Ubuntu 18.04 LTS users are advised to use the PPA. On Debian buster we recommend to use the backports package.
You can also install one of the released packages, or clone Firejail’s source code from our Git repository and compile manually:
$ git clone https://github.com/netblue30/firejail.git
$ cd firejail
$ ./configure && make && sudo make install-strip
On Debian/Ubuntu you will need to install git and gcc compiler. AppArmor development libraries and pkg-config are required when using --apparmor ./configure option:
$ sudo apt-get install git build-essential libapparmor-dev pkg-config gawk
For --selinux option, add libselinux1-dev (libselinux-devel for Fedora).
Detailed information on using firejail from git is available on the wiki.
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
Run "firejail --list" in a terminal to list all active sandboxes. Example:
$ firejail --list
1617:netblue:/usr/bin/firejail /usr/bin/firefox-esr
7719:netblue:/usr/bin/firejail /usr/bin/transmission-qt
7779:netblue:/usr/bin/firejail /usr/bin/galculator
7874:netblue:/usr/bin/firejail /usr/bin/vlc --started-from-file file:///home/netblue/firejail-whitelist.mp4
7916:netblue:firejail --list
Integrate your sandbox into your desktop by running the following two commands:
$ firecfg --fix-sound
$ sudo firecfg
The first command solves some shared memory/PID namespace bugs in PulseAudio software prior to version 9. The second command integrates Firejail into your desktop. You would need to logout and login back to apply PulseAudio changes.
Start your programs the way you are used to: desktop manager menus, file manager, desktop launchers. The integration applies to any program supported by default by Firejail. There are about 250 default applications in current Firejail version, and the number goes up with every new release. We keep the application list in /usr/lib/firejail/firecfg.config file.
Most Firejail command line options can be passed to the sandbox using profile files. You can find the profiles for all supported applications in /etc/firejail directory.
If you keep additional Firejail security profiles in a public repository, please give us a link:
Use this issue to request new profiles: #1139
You can also use this tool to get a list of syscalls needed by a program: contrib/syscalls.sh.
We also keep a list of profile fixes for previous released versions in etc-fixes directory.
Milestone page: https://github.com/netblue30/firejail/milestone/1 Release discussion: netblue30#3696
JAILTEST(1) JAILTEST man page JAILTEST(1)
NAME
jailtest - Simple utility program to test running sandboxes
SYNOPSIS
sudo jailtest [OPTIONS] [directory]
DESCRIPTION
WORK IN PROGRESS! jailtest attaches itself to all sandboxes started by
the user and performs some basic tests on the sandbox filesystem:
1. Virtual directories
jailtest extracts a list with the main virtual directories in‐
stalled by the sandbox. These directories are build by firejail
at startup using --private* and --whitelist commands.
2. Noexec test
jailtest inserts executable programs in /home/username, /tmp,
and /var/tmp directories and tries to run them form inside the
sandbox, thus testing if the directory is executable or not.
3. Read access test
jailtest creates test files in the directories specified by the
user and tries to read them from inside the sandbox.
4. AppArmor test
5. Seccomp test
The program is started as root using sudo.
OPTIONS
--debug
Print debug messages
-?, --help
Print options end exit.
--version
Print program version and exit.
[directory]
One or more directories in user home to test for read access.
~/.ssh and ~/.gnupg are tested by default.
OUTPUT
For each sandbox detected we print the following line:
PID:USER:Sandbox Name:Command
It is followed by relevant sandbox information, such as the virtual di‐
rectories and various warnings.
EXAMPLE
$ sudo jailtest
2014:netblue::firejail /usr/bin/gimp
Virtual dirs: /tmp, /var/tmp, /dev, /usr/share,
Warning: I can run programs in /home/netblue
2055:netblue::firejail /usr/bin/ssh -X netblue@x.y.z.net
Virtual dirs: /var/tmp, /dev, /usr/share, /run/user/1000,
Warning: I can read ~/.ssh
2186:netblue:libreoffice:firejail --appimage /opt/LibreOffice-fresh.ap‐
pimage
Virtual dirs: /tmp, /var/tmp, /dev,
26090:netblue::/usr/bin/firejail /opt/firefox/firefox
Virtual dirs: /home/netblue, /tmp, /var/tmp, /dev, /etc, /usr/share,
/run/user/1000,
26160:netblue:tor:firejail --private=~/tor-browser_en-US ./start-tor
Warning: AppArmor not enabled
Virtual dirs: /home/netblue, /tmp, /var/tmp, /dev, /etc, /bin,
/usr/share, /run/user/1000,
Warning: I can run programs in /home/netblue
LICENSE
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
Homepage: https://firejail.wordpress.com
SEE ALSO
firejail(1), firemon(1), firecfg(1), firejail-profile(5), firejail-lo‐
gin(5), firejail-users(5),
0.9.65 Feb 2021 JAILTEST(1)
A small tool to print profile statistics. Compile as usual and run in /etc/profiles:
$ sudo cp src/profstats/profstats /etc/firejail/.
$ cd /etc/firejail
$ ./profstats *.profile
Warning: multiple caps in transmission-daemon.profile
Stats:
profiles 1077
include local profile 1077 (include profile-name.local)
include globals 1077 (include globals.local)
blacklist ~/.ssh 971 (include disable-common.inc)
seccomp 988
capabilities 1076
noexec 960 (include disable-exec.inc)
memory-deny-write-execute 231
apparmor 621
private-bin 571
private-dev 949
private-etc 470
private-tmp 835
whitelist home directory 508
whitelist var 758 (include whitelist-var-common.inc)
whitelist run/user 539 (include whitelist-runuser-common.inc
or blacklist ${RUNUSER})
whitelist usr/share 526 (include whitelist-usr-share-common.inc
net none 354
dbus-user none 573
dbus-user filter 86
dbus-system none 706
dbus-system filter 7
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