How to Disable SSH Login for the Root user?

If you set a good password, you can protect your server from brute force attack. But it may still be possible attacker can still make brute force attack. The following instructions are for disabling the root user and allowing another user to assume the root users permissions. This adds another layer of security because an additional username and password must now be entered before gaining the root user privileges.

This article describes how to disable SSH logins for the root account. For security reasons, you should create a normal user account, and then disable SSH logins for the root account as soon as possible.

Creating a Normal User Account

Before you disable SSH logins for the root account, you must create a normal user account. (Otherwise, you will be unable to access your server when you disable the root account for SSH logins.)

Follow the below steps to create a normal user account:

1. Add the user. In the following example, we will use the user name admin. The command adduser will automatically create the user, initial group, and home directory.

[root@root ~]# adduser admin
[root@root ~]# id admin
uid=10018(admin) gid=10018(admin) groups=10018(admin)
[root@root ~]# ls -lad /home/admin/
drwx------ 2 admin admin 4096 Jun 25 16:01 /home/admin/

2. Set the password for the admin user. When prompted, type and then retype the password.

[root@root ~]# passwd admin
Changing password for user admin.
New UNIX password:
Retype new UNIX password:
passwd: all authentication tokens updated successfully.
[root@root ~]#

3. For sudo permissions for your new admin user, use the following command.

[root@root ~]# echo 'admin ALL=(ALL) ALL' >> /etc/sudoers

4. SSH to the server with the new admin user and ensure that the login works.

[root@root ~]# ssh [email protected]
[email protected]'s password:
[admin@admin ~]$

5. Verify that you can su (switch user) to root with the admin user.

[admin@admin ~]$ su -
Password:
[root@root ~]$ whoami
root

6. To disable root SSH login, edit /etc/ssh/sshd_config with your favorite text editor.

[root@root ~]# vi /etc/ssh/sshd_config

Change this line:

#PermitRootLogin yes

Edit to this:

PermitRootLogin no

7. Ensure that you are logged into the box with another shell before restarting sshd to avoid locking yourself out of the server.

[root@root ~]# /etc/init.d/sshd restart
Stopping sshd: [ OK ]
Starting sshd: [ OK ]
[root@root ~]#

You will now be able to connect to your server via ssh with the admin user and then use the command su to switch to the root user.