iPhone bug lets callers eavesdrop

A newly discovered FaceTime bug lets people hear and even see those they are reaching out to on iPhones even if the other person hasn't answered their phone.

When a phone number is dialed on FaceTime -- the iPhone's internet-based voice and video calling feature -- the caller can swipe up from the bottom of the screen and tap an option to add a person, according to video demonstrations.

If the caller then enters their own number as that of the added caller, a group call begins even though the person being called hasn't even answered.

The caller can then eavesdrop on the person being called, and in some demonstrations even watch them through the camera app. Declining a call breaks the connection.

The bug, initially outlined by Apple product and review website 9to5Mac.com, was reported by several media outlets.

A video posted at Twitter account @BmManski showing how simple it is to take advantage of the flaw and listen in on an iPhone being called using FaceTime, logged nearly two million views and was shared 14,000 times by late evening in California.

Some Twitter users offered advice to disable the FaceTime application until a fix was in place.