Users, GRANT, REVOKE and Least Privilege

What this card says

What it is

GRANT gives a database user permissions. REVOKE takes them away.

Least privilege = give only what is needed.

Why it matters for security

If the web app uses root, one SQL injection controls the whole database.

With a limited user, the attacker cannot drop databases or write files.

Common mistake

GRANT ALL PRIVILEGES ON *.* TO 'app'@'%' gives everything, from anywhere.

Better: GRANT SELECT, INSERT, UPDATE ON shop.* TO 'app'@'localhost';