How do you disable anonymous login?

According to the MySQL documentation, you can harden a MySQL server by adding passwords, or removing the anonymous accounts.


If you want to prevent clients from connecting as anonymous users
without a password, you should either assign a password to each
anonymous account or else remove the accounts.

Before hardening, my users table looked like this.

mysql> select user,host,password from mysql.user;
+------------------+-----------+-------------------------------------------+
| user             | host      | password                                  |
+------------------+-----------+-------------------------------------------+
| root             | localhost | *F3A2A51A9B0F2BE246XXXXXXXXXXXXXXXXXXXXXX |
| root             | gitlab    |                                           |
| root             | 127.0.0.1 |                                           |
| root             | ::1       |                                           |
|                  | localhost |                                           |
|                  | gitlab    |                                           |
| debian-sys-maint | localhost | *95C1BF709B26A5BAXXXXXXXXXXXXXXXXXXXXXXXX |
| myuser           | localhost | *6C8989366EAF75BB6XXXXXXXXXXXXXXXXXXXXXXX |
+------------------+-----------+-------------------------------------------+

I've remove all anonymous accounts, so that the user table now looks like this.
(I'm using puppet to manage the users, but puppet effectively performs a DROP USER command).

```
mysql> select user,host,password from mysql.user;
+------------------+-----------+-------------------------------------------+
| user | host | password |
+------------------+-----------+-------------------------------------------+
| root | localhost | *F3A2A51A9B0F2BE246XXXXXXXXXXXXXXXXXXXXXX |
| debian-sys-maint | localhost | *95C1BF709B26A5BAXXXXXXXXXXXXXXXXXXXXXXXX |
| myuser | localhost | *6

I figured it out. While /etc/mysql/my.cnf didn't have a password keypair stored, there was a password stored in /root/.my.cnf.

As soon as I commented out the password in /root/.my.cnf, I was not allowed to log in without a password (which is what I expected).

StackExchange Database Administrators Q#51452, answer score: 6