YunoHost has been developed to provide the best security without too much complication. Every protocol used in YunoHost is encrypted, only password's hashes are stored and by default each user is able to access their personal directory only.
Two things remain important to note:
Installing additional apps can significantly increase the number of potential security flaws. Do not hesitate to get information about security flaws before installing an app, and try to install only apps which will suit your needs.
The fact that YunoHost is a well-spread software increases the chances of an attack. If a flaw is discovered, it could potentially affect all the YunoHost instances at once. Keep your system up-to-date to remain safe.
If you need advice, do not hesitate to ask us.
To discuss security flaws, contact the YunoHost security team.
If your YunoHost server is used in a critical production environment, or if you want to improve its safety, you may want to follow those good practices.
Attention: Following those instructions requires advanced knowledge of system administration.
By default, the SSH authentication uses the administration password. Deactivating this kind of authentication and replacing it by a key mechanism is advised.
On your client:
ssh-keygen ssh-copy-id -i ~/.ssh/id_rsa.pub <username@your_yunohost_server>
If you meet permissions issues, set
username as owner of the dir
chown. Be careful, for security reason this directory should be in mode
Type your admnistration password and your key will be copied on your server.
On your server, edit the SSH configuration file, in order to deactivate the password authentication.
nano /etc/ssh/sshd_config # Modify or add the following line PasswordAuthentication no
Save and restart the SSH daemon.
systemctl restart ssh
To prevent SSH connection attempts by robots that scan the Internet for any server with SSH enabled, you can change the SSH port.
On your server, edit the ssh configuration file, in order to modify the SSH port.
Search the line "Port" and replace port number (by default 22) by another unused number
# What ports, IPs and protocols we listen for Port 22 # to replace by 9777 for example
Open the port in the firewall (you can use
-6 option to deny ipv4 connection)
yunohost firewall allow TCP 9777
Save and restart the SSH daemon. Switch over to the new port by restarting SSH.
systemctl restart ssh
Then restart the iptables firewall and close the old port in iptables.
yunohost firewall reload yunohost firewall disallow TCP <your_old_ssh_port_number> # port by default 22
You also need to give
fail2ban the new SSH port.
To do that you need to create the configuration file
my_ssh_port.conf with the command
and you can then fill it in with
[sshd] port = <your_ssh_port> [sshd-ddos] port = <your_ssh_port>
Finally you have to restart
fail2ban in order to apply the new configuration
systemctl restart fail2ban
For the next SSH connections , you need to add the
-p option followed by the SSH port number.
ssh -p <new_ssh_port_number> admin@<your_yunohost_server>
The default TLS configuration for services tends to offer good compatibility to support old devices. You can tune this policy for specific services like SSH and NGINX. By default, the NGINX configuration follows the intermediate compatibility recommendation from Mozilla. You can choose to switch to the 'modern' configuration which uses more recent security recommendations, but decreases the compatibility, which may be an issue for your users and visitors using older devices. More details about the compatibility can be found on this page.
Changing the compatibility level is not definitive and can be reverted if it doesn't fit with your environment.
On your server, change the policy for NGINX
sudo yunohost settings set security.nginx.compatibility -v modern
On your server, change the policy for SSH
sudo yunohost settings set security.ssh.compatibility -v modern
YunoHost administration is accessible through an HTTP API, served on the 6787 port by default (only on
localhost). It can be used to administer a lot of things on your server, so malicious actors can also use it to damage your server. The best thing to do, if you know how to use the command-line interface, is to deactivate the
sudo systemctl disable yunohost-api sudo systemctl stop yunohost-api
Found errors? Think you can improve this documentation? Simply click the Edit link at the top of the page, and then the icon on Github to suggest changes.