[barkingcat]

If you read the story you would see that the database host is a shared host (as in hundreds of other clients of the Webhost have accounts on it) and that the error is likely the result of a persistent hack. As in there is a vulnerability where someone can get access to the server and create a passwordless root account, so that they can siphon the data out.

Once that account is deleted, a new passwordless root account is created by the attacker in order to continue access.