Prevent MySQL login with no user or password

Question

I installed MySQL like so:

sudo apt install mysql-server -y && mysql_secure_installation;

and did the following

CREATE USER 'user'@'localhost' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON * . * TO 'user'@'localhost';
FLUSH PRIVILEGES;

ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';
FLUSH PRIVILEGES;

However, I can still access MySQL with:

sudo mysql

I don't understand how it has access with no user or password... How do I prevent this?

Answer 1

when you run sudo mysql command its authenticated with auth socket, you can check authentication used using query below.

mysql> SELECT plugin from mysql.user where User='root';

if you wnat disable that and using native authentication, run this query.

mysql> UPDATE mysql.user SET plugin = 'mysql_native_password', authentication_string = PASSWORD('changeme') WHERE User = 'root';
mysql> FLUSH PRIVILEGES;

and if you need more information, you can read docs about auth socket.