If you haven't enabled two-factor authentication quite yet, you might want to get on it. Yes, right now. A new vulnerability has been found that will allow a malicious user to reset a user's password by knowing just their e-mail address and date of birth. It's not clear if this bug resulted from Apple's new two-step authentication or if it has always been there.
A guide to doing the hack has been posted online, though we will not be linking to it for some very obvious security reasons. A malicious user has to simply paste in a modified URL and answer the date of birth security question to reset the password. The exploit makes use of Apple's iForgot tool.