Halo 4 isn't in beta. We all know this. But just in case, Microsoft has warned gamers against phishing scams purporting to be Halo 4 beta invites. 343 Industries' David Ellis recently dropped the confirmation on Twitter, complete with excellent Star Trek meme.
"If you see a page claiming to allow you to sign up for a Halo 4 beta be advised, IT'S A FAKE."
A quick Google search was enough to find a couple of fairly convincing fronts. With Xbox Live account security a major concern at the moment, and strong passwords a must, make sure you don't fall prey to this fairly obvious trap. Treat any and all emails that encourage you to divulge personal information with extreme suspicion.