Disable Password Logins and Root Login Access

These instructions are intended for all users that want to reduce the risk of brute force login attacks by disabling password logins and root login access. These procedures will improve security on your Linux VPS by requiring the correct SSH Key to be able to login. After completing these steps, any computer, or SSH session, that does not have the correct SSH Key installed will not be able to login to the Linux VPS, and you will no longer be able to remotely login to the Linux VPS using the root user.

Disabling password login capabilities

Warning

Do not perform the following steps until you are able to successfully login to the Linux VPS using an SSH key rather than your username and password.

  1. Connect to the Linux VPS and login as the rupxmn user.

  2. Elevate to the root user. This is necessary because the other steps in this process require elevated privileges:

    sudo -i
    
  3. The following commands will edit the SSH file /etc/ssh/sshd_config to disable password login capabilities, and will then restart the sshd service to apply the change:

    sed -i 's/PasswordAuthentication yes/PasswordAuthentication no/g' /etc/ssh/sshd_config
    systemctl reload sshd
    

Disabling root login access

Warning

Do not perform the following steps until you have created the user rupxmn and are able to login to the Linux VPS using an SSH key with that new user.

  • You should be logged in to the Linux VPS as the root user to complete the following steps:
  1. The following commands will edit the SSH file /etc/ssh/sshd_config to disable root login access, and will then restart the sshd service to apply the change:

    sed -i 's/PermitRootLogin yes/PermitRootLogin no/g' /etc/ssh/sshd_config
    systemctl reload sshd
    

Let’s test it!

  1. Open a duplicate session to the Linux VPS and login as root.
  • NOTE: It should no longer allow you to login as root and a pop up window should appear with the following error: Disconnected: No supported authentication methods available

If password authentication and root login access have been successfully disabled then you can proceed to the next section to configure logrotate.