This scam is old as hills, but scammers are still using and making money of unsuspecting people. So we thought that a warning is in order.
Today, one of our senior researchers received a call from unknown international number and when he answered the call, it was immediately dropped. And being used to receiving calls from reporters from around the world he might have done the obvious thing and called the number back.
But what he did instead was to perform a Google search on the number. He discovered there are a lot of other people who have received calls from same number and wondered what the calls are about, and more importantly people who called back and are complaining about mysterious charges on their phone bill.
The scam used by fraudsters is very simple. Set up a premium rate number, use that number to call a group of randomly selected phone numbers and either let the phone ring only once, or cut the call immediately after receiver answers the call.
Then simply wait for curious people to call back, play an "busy tone" audio file to make the caller think that call did not connect, and then rake in the profits.
Usually these numbers charge something in between 1 to 5€, a big enough sum to make money if you can fool thousands of people into calling, small enough to make complaints impractical.
The best way to avoid this scam is to be wary of unknown numbers and not to call them back immediately. If the number looks something you have not seen before and the country code is something you haven't even heard of run a Google or WhoCallsMe search on the number before calling back.