Creating root user account on Ubuntu Server

To enable the Root account (i.e. set a password) use:

sudo passwd root

Re-disabling your root account

sudo passwd -dl root

Background Information

In Linux (and Unix in general), there is a SuperUser named Root. The Windows equivalent of Root is Administrators group. The SuperUser can do anything and everything, and thus doing daily work as the SuperUser can be dangerous. You could type a command incorrectly and destroy the system. Ideally, you run as a user that has only the privileges needed for the task at hand. In some cases, this is necessarily Root, but most of the time it is a regular user.

By default, the Root account password is locked in Ubuntu. This means that you cannot login as Root directly or use the su command to become the Root user. However, since the Root account physically exists it is still possible to run programs with root-level privileges. This is where sudo comes in – it allows authorized users (normally “Administrative” users; for further information please refer toAddUsersHowto) to run certain programs as Root without having to know the root password.

This means that in the terminal you should use sudo for commands that require root privileges; simply prepend sudo to all the commands you would normally run as Root. For more extensive usage examples, please see below. Similarly, when you run GUI programs that require root privileges (e.g. the network configuration applet), use graphical sudo and you will also be prompted for a password (more below). Just remember, when sudo asks for a password, it needs YOUR USER password, and not the Root account password.

Please keep in mind, a substantial number of Ubuntu users are new to Linux. There is a learning curve associated with any OS and many new users try to take shortcuts by enabling the root account, logging in as root, and changing ownership of system files.

Example: Broken system via (ab)use of root by a new user

Please note: At the time of the post, this was the users first post on the Ubuntu forums. While some may say this is a “learning experience”, learning by breaking your system is frustrating and can result in data loss.

When giving advice on the Ubuntu Forums and IRC, please take the time to teach “the basics” such as ownership, permissions, and how to use sudo / gksu / kdesudo in such a way that new users do not break systems.

 

Advantages and Disadvantages

 

Benefits of using sudo

Some benefits of leaving Root logins disabled by default include the following:

  • The Ubuntu installer has fewer questions to ask.
  • Users don’t have to remember an extra password (i.e. the root password), which they are likely to forget (or write down so anyone can crack into their account easily).
  • It avoids the “I can do anything” interactive login by default (e.g. the tendency by users to login as an “Administrator” user in Microsoft Windows systems), you will be prompted for a password before major changes can happen, which should make you think about the consequences of what you are doing.
  • sudo adds a log entry of the command(s) run (in /var/log/auth.log). If you mess up, you can always go back and see what commands were run. It is also nice for auditing.
  • Every cracker trying to brute-force their way into your box will know it has an account named Root and will try that first. What they don’t know is what the usernames of your other users are. Since the Root account password is locked, this attack becomes essentially meaningless, since there is no password to crack or guess in the first place.
  • Allows easy transfer for admin rights, in a short term or long term period, by adding and removing users from groups, while not compromising the Root account.
  • sudo can be setup with a much more fine-grained security policy.
  • The Root account password does not need to be shared with everybody who needs to perform some type of administrative task(s) on the system (see the previous bullet).
  • The authentication automatically expires after a short time (which can be set to as little as desired or 0); so if you walk away from the terminal after running commands as Root using sudo, you will not be leaving a Root terminal open indefinitely.

 

Downsides of using sudo

Although for desktops the benefits of using sudo are great, there are possible issues which need to be noted:

  • Redirecting the output of commands run with sudo requires a different approach. For instance consider sudo ls > /root/somefile will not work since it is the shell that tries to write to that file. You can use ls | sudo tee -a /root/somefile to append, orls | sudo tee /root/somefile to overwrite contents. You could also pass the whole command to a shell process run under sudo to have the file written to with root permissions, such as sudo sh -c "ls > /root/somefile".
  • In a lot of office environments the ONLY local user on a system is Root. All other users are imported using NSS techniques such as nss-ldap. To setup a workstation, or fix it, in the case of a network failure where nss-ldap is broken, Root is required. This tends to leave the system unusable unless cracked. An extra local user, or an enabled Root password is needed here. The local user account should have its $HOME on a local disk, _not_ on NFS (or any other networked filesystem), and a .profile/.bashrc that doesn’t reference any files on NFS mounts. This is usually the case for Root, but if adding a non-Root rescue account, you will have to take these precautions manually.
    • Alternatively, a sysadmin type account can be implemented as a local user on all systems, and granted proper sudo privileges. As explained in the benefits section above, commands can be easily tracked and audited.

 

 

 

 

 

Usage

  • When using sudo, your password is stored by default for 15 minutes. After that time, you will need to enter your password again.
  • Your password will not be shown on the screen as you type it, not even as a row of stars (******). It is being entered with each keystroke!

 

sudo

To use sudo on the command line, preface the command with sudo, as below: Example #1

sudo chown bob:bob /home/bob/*

Example #2

sudo /etc/init.d/networking restart

To repeat the last command entered, except with sudo prepended to it, run:

sudo !!
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