A vulnerability in Apple’s FaceTime can be used to spy on people. This had forced Apple to disable some features on the app to prevent abuse until a patch is released.
It is known that the attack does not require any technical knowledge and can be carried out in seconds.
All that the attacker has to do is create a group chat on Facetime and add hisown number to it. This makes the app treat the action as if the targeted user answered a call allowing the hacker to listen to the victims activities.