Changing the root password in Ubuntu just involves a few lines of code in the terminal.

A vulnerability in GNOME Display Manager (gdm) could allow a standard user to create accounts with increased privileges, giving a local attacker a path to run code with administrator permissions ...

Use the "sudo" command to edit the file as the root user and use the nano text editor that is standard with Ubuntu. For example, to create and open the file in nano type:sudo nano /etc/apache2 ...