He can do it once, maybe, if you don't authenticate the server. With a password, he can do it any number of time, to any number of targets, and there's no way t

He can do it once, maybe, if you don't authenticate the server. With a password, he can do it any number of time, to any number of targets, and there's no way to catch it. Yes, it is still not perfect, but here's the advantage.