Mitnick is a very nice guy and all. But he's not the world's greatest hacker. Back in the day, he was good at some phone stuff (which has radically changed) and social engineering. Just an aside, he is a pretty good security guy.
And yes, it has vulnerabilities. They did a crap job on infrastructure. Generally, security is usually worse than a place's infrastructure. That should tell ya how bad I suspect it is.