A bug forced Apple to temporarily disable Group calls on FaceTime: users' privacy was at risk. What's happening
FaceTime, Apple's video messaging service, also has its flaws and the latest one discovered is also very serious: if you call through FaceTime you can listen to what the microphone is picking up at that moment, even if the user doesn't answer the call. Apple is aware of the flaw and has disabled the group calling feature in FaceTime but is working on a fix for this serious bug and plans to release a corrected version of FaceTime within this week.
The problem was discovered by some users who immediately posted videos on social networks showing the FaceTime bug. The news was immediately reported by the main US news sites and within a few hours it became public knowledge. It's a bug that needs to be fixed pretty quickly, since it puts users' privacy at risk.
FaceTime Bug, what's happening
The bug works like this: if you call another user from your iPhone via FaceTime Video, even before he answers the call you can swipe up and add your phone number to the video call. At this point FaceTime "gets confused" and thinks that a group video call has already started, and starts sending you the audio of the other person who hasn't answered yet. As soon as the bug kicks in, the FaceTime app stops ringing because it thinks there's been an answer. But there's also a bug in the bug: if the receiver presses the iPhone's power or volume button to mute the call, then even the video captured by their camera is transmitted to the caller. The bug also repeats itself from Mac computers, whether the Mac is the caller or the receiver. For this to happen, both smartphones or Macs need to be compatible with Group FaceTime, which is the version of the app that lets you do video conferencing (Apple's equivalent of Google Hangouts for Android).
How to protect yourself from the FaceTime bug
While waiting for Apple to correct this serious problem that seriously jeopardizes users' privacy, the only thing you can do is disable the FaceTime app by going into the iPhone's settings and tapping the relevant switch. From Mac, instead, you have to enter the FaceTime preferences and disable "Enable this account". In this way, you won't be able to be contacted (and therefore spied on without your knowledge) via FaceTime.
Those who prefer to wait for Apple to solve the problem must take into account that, every time they receive a call via FaceTime, someone on the other side could hear and see them. You should also consider the fact that the unintentional transmission of audio and video only ends when we reject the call, and not when we silence the FaceTime ringtone. Theoretically, then, we could be spied on for a very long time without even realizing it.
Apple has, however, run for cover by disabling group calls on FaceTime. They will only be reactivated when the new version of the app is released.