If you have service from AT&T or Comcast you know they're promoting their free WiFi hotspots like crazy.
Well, the Bad Guys have discovered this, and place wireless routers that broadcast names of "attwifi" or "xfinitywifi" in likely places. If your phone is set up to associate with such a hotspot automagically, it will connect to the evil hotspot. If the attackers spoof a login screen, you could transmit your AT&T or Comcast password to the operators of the evil hotspot. Even if there's no login, you're on a network you think you can trust, but you can't.
What to do? Don't allow your gear to connect automatically. Consider where you are if your gear asks for permission to connect, and never, ever use your carrier's WiFi password for anything else. Especially not for your email account, because if the Bad Guys can take over your email, they can probably reset your passwords for other accounts... like your bank.
Hack Your WiFi Password? Easy! by Bob Brown is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.