'debian-sys-maint'@'localhost' privileges on Ubuntu

Question

So I've changed my server OS to Ubuntu, which comes with a 'debian-sys-maint' SQL user when you install MySQL.

Now the problem: If you don't have the user or it's got "insufficient" permissions, you will get a warning message. Tutorials around the web show granting "ALL" permissions to the given MySQL user.

I don't think that's a good security move.
What permissions does that user really needs?

Answer 1

If you already have root@localhost (which has all privileges activated), then having that user would be kind of redundant. It would only be of use if you logged into mysql on that machine using DNS. That's unnecessary because root@localhost will connect to mysql via a socket file.

If would OK to just remove that user.

Once you log into mysql as root@localhost you can remove that user with this:

DELETE FROM mysql.user WHERE user='debian-sys-maint';
FLUSH PRIVILEGES;

For further information on what grants there are for users, check out the MySQL Documentation on User Grants.