What is Wangiri fraud?
A call from an unfamiliar number comes into your cellphone, rings once and disconnects. It looks innocuous, like a simple mistake. However, it may actually be more sinister— you may have been targeted by “Wangiri" attacks, Japanese for “one ring and drop", a missed call fraud campaign that began in Japan. In Wangiri fraud, a scammer places a robocall to a mobile number (the target subscriber) and hangs up after one or two rings. They often do so more than once, with the objective of getting the person to call back. Some use an SMS to achieve the same goal. This is the first “leg" of the scheme.
In Wangiri fraud scammers manipulate the A-number field (the CLI) to display the same number for the calls, usually a hijacked number or a premium/high-rated destination number on an International Premium Rate Service. If the target subscriber does call back, they have unwittingly dialed an extremely expensive number. Usually, they then hear an adult-oriented or lottery win/gambling recording that serves as a pretext to keep the caller on the line as long as possible. The victim is saddled with expensive fees, some of which are paid to the scammer. This is the second “leg" of the fraud.
The impact of Wangiri fraud
It's clear why Wangiri is attractive to scammers. There are few costs to the fraudster, as the initial call is not charged because the majority of calls are disconnected before the target subscriber answers. Only a small percentage of the target subscribers actually call the scammers back. However, Wangiri fraudsters still turn a profit by working en masse, often generating more than 300,000 calls a day to one or more targeted mobile operators.
The damage to telcos is staggering. Target subscribers who do call the scammers back receive an unpleasant surprise when their next phone bill arrives, and almost always dispute the charge with their mobile carrier. Telcos are forced to either refund the costs, or risk losing the customer. The CFCA rates Wangiri fraud as one of the top five telecom fraud risks and estimates the losses from Wangiri attacks at $1.8 billion in 2019 alone. In addition to the financial losses, the volume of calls in Wangiri fraud places a significant burden on the operators, who may not have enough available circuits to put through legitimate calls.
Wangiri fraud detection & protection
Most fraud management systems are ineffective at dealing with Wangiri. The first leg is very difficult to track as it has no chargeable duration. There is also a lack of visibility—the carrier who terminates the call can't tell of the originating country is high risk or not. In the second leg, the main wholesale carrier that transits the calls back to the fraudulent number range can sometimes block the breakout by identifying a problematic pattern, but even then, the problem isn't solved. The mobile operator often simply overflows the calls to alternative wholesale carriers. No single carrier can overcome the problem alone—industry collaboration is the only way to stop Wangiri fraud from escalating.
Changing the paradigm
AB Handshake is the first solution that brings telcos together to fight global fraud risk more effectively. Rather than a never-ending race to stay one step ahead of the scammers and identify Wangiri attacks and other fraud schemes through sampling, patterns, and statistics, telcos who join the AB Handshake community use a common 'handshake' to validate each and every call from both ends. If either side is unable to validate the call, it is blocked in real time. There is no need to try to track patterns, or pre-emptively block expensive destinations. Since the validation begins in parallel to the call setup, it targets both legs of the Wangiri fraud scheme.
Wangiri is a significant fraud risk, and one of the most difficult for traditional fraud protection tools to prevent. By joining the AB Handshake community, telcos both ensure their own security and contribute to fighting Wangiri fraud worldwide.