You receive a call to your mobile phone from an unfamiliar number. Only one ring, and then the caller hangs up. Instinctively many receivers will return the call, and in doing so risk becoming a victim of a "Wangiri" fraud scam, and losing significant amounts of money.

The scam impacts consumers throughout the world. After receiving a lot of consumer complaints over the past two years, the Federal Communications Commission (FCC) alerted consumers to reported waves of robocalls, which targeted specific U.S. area codes. This continuous problem sees fraudsters placing automated telephone calls to mobile numbers, and then hanging up after one or two rings. Scammers try this a few times prompting their targets to return the call, except when they do, the victim is charged long distance, international fees to connect the call, and an inflated amount for every subsequent minute they remain on the line. And while many will ignore an international phone number they don’t recognize, other more vulnerable mobile users, such as young or elderly people who are unaware of international and regional dialing codes, may return the call without a second thought. The result is bill shock; one article reports of customers receiving a charge for a 12-hour premium rate conversation after returning a Wangiri scam call.

Wangiri isn’t a new concept, and originating in Japan, it translates as "one ring and cut". Fraudsters now operate on an industrial scale, indiscriminately targeting whole groups of population rather than specific individuals. According to the Fraud & Technology Wire, Wangiri amounted to $2billion worth of losses globally in 2014 – a large chunk of the estimated €29 billion-a-year cost of telecommunications fraud. It is not confined to specific regions; nor does it target specific mobile networks.

Furthermore, new technologies such as cloud communications platforms – whilst improving communication – are enabling fraudsters to generate missed calls to up to 3,000 targets at once. And it was this increase in Wangiri calls which prompted the FCC to release its consumer alert in May this year, and other government agencies around the world, to take action with public communications through written and audio-visual mass media reach.

So how can this pervasive method of fraud be mitigated?

One ring, one solution?

For many Wangiri attempts, the solution is simply not to pick up. If the call remains unanswered and is not returned, fraudsters cannot force the connection and therefore cannot monetize the call. As the majority of Wangiri calls are from overseas numbers – such as Sierra Leone, Papua New Guinea, Liberia, the Cook Islands and Tunisia – unless a caller has family or friends in the region, it is unlikely a call from one of these countries is legitimate.

However, as mentioned earlier, many mobile subscribers will ignore calls from an international phone number that they don’t recognize, so scammers are beginning to use more advanced tactics to snare their victims. One example is for fraudsters to adopt a local-looking phone number which tricks consumers into returning the call. This evolution of Wangiri fraud means that now more than ever, consumers need to stay vigilant.

For mobile operators and other telcos, Wangiri is part of a much bigger problem: Wangiri is used as a method of sending traffic to fraudulent numbers around the world. This contributes to another of the most prevalent telecoms frauds, International Revenue Share Fraud (IRSF), which alone costs the industry between $4 billion and $6.1 billion, annually. So, what is the answer for operators?

In this photo, an attendee inspects the new phone during a Google media event in San Francisco, California, Sept. 29, 2015. Getty Images/ Justin Sullivan

Stop, collaborate, and crowdsource

Operators need to fight back. By sharing intelligence and occurrences of any type of telecoms fraud, operators and telecommunications players stand a better chance of tackling the threat. For example, by taking a collaborative approach to tackling telecoms fraud, encouraging operators to share intel they have on fraud and the impact it’s having on its network, the chances of other operators and consumers being hit by fraud schemes such as Wangiri or IRSF will be greatly reduced.

This collaborative approach can be supported by new technologies, such as machine learning, that can enable operators to identify suspect behaviors and anomalies fast enough and, by doing so, encourage a more proactive approach to fraud identification and prevention.

A fraud-free future

A recent industry report published by the ITW Global Leaders’ Forum states that “85% of carriers cite fraud as a priority for their organisation, with 74% saying that it’s growing in importance.” Some operators are looking to mitigate the impact of Wangiri with network technology that proactively blocks fraudulent calls. And along with the FCC’s recent alert and the subsequent media coverage and helpful articles which can be found online, awareness of the threat and costly implications of Wangiri are at an all-time high.

Unfortunately, it is near impossible to completely eliminate fraud. Fraudsters will always be looking for new ways to exploit telecommunications companies and their customers, in order to be successful in their criminal activity and make money. But, if consumers stay vigilant, and operators adopt a fast collaborative approach, both parties can make great strides in the fight against fraud.

(Katia González is the head of Fraud Prevention at BICS, a leading global wholesale carrier in the telecom industry.)