Malware can grant hackers unfettered access to your devices, and this time even turning off your phone can't stop them. AVG security has dubbed this threat PowerOffHijack. It's so called because it actually hijacks your ability to turn off your phone. This malware creates a false shutdown screen, so the user thinks he is turning off his phone. The screen turns black and it looks like any other time your phone has been turned off. In fact, the device is still on and just as capable of being controlled by an outside user.