AT&T warns billions of iPhone and Android owners over bank-emptying ‘one ring’ call – don’t ignore trick to stay safe

SMARTPHONE owners are being warned over a dangerous scam known as "wangiri" – or the "one ring" attack.

It drains cash from your bank, and it works using a very sneaky trick.

An official security memo from AT&T reveals exactly how the dastardly scam works.

It all seems very innocent at first: your iPhone or Android rings once, and then the call stops.

The person on the other end is hoping that you'll call back to investigate – and that's when the danger begins.

"As soon as you do, you’ll hear a recorded message that is intended to keep you on the phone, or worse, to get you to call back a second time," AT&T explained.

"For example, the message may say: 'Hello … hello? … I’m having trouble hearing you. Hello? … Will you please call back?'

"Every time you call, you will be charged high international rates or other connection fees. The bad guy gets all or part of those fees."

They may also employ tricks to keep you on the phone.

For instance, you could be told that if you listen to a full song on the call, you'll receive a prize, reward or gift at the end.

But the longer you stay on the call, the more you end up paying – helping the cybercriminals make a quick profit.

According to AT&T, this type of scam is known as "wangiri".

It comes from Japan "where the scam originated years ago and means "one-ring-and-cut".

How to stay safe

The best way to stay safe is to simply ignore calls from suspicious phone numbers.

"Do not answer calls from numbers you do not recognize," AT&T advised.

"This is good advice in general, because it can help protect you from other scams, such as spoofing.

"If you receive a one-ring call from an unknown number, do not call that number back."

AT&T also warned to look out for a + appearing ahead of the area code on calls.

That signals that an international call is being placed, which will result in extra charges.

If you see this and it seems suspicious, it's best to hang up immediately.