If you received phone calls from an unknown overseas number yesterday, you weren’t the only one. In the past few days there’s been an increase in attempts at a spam technique known as ‘Wangiri’.

On Facebook there were dozens of people over the past days who reported that they have received calls, usually from numbers beginning with 0041 (Switzerland) or else an African extension.

The reason for this is that there are fraudsters that would have compromised the system that manages interconnect charges internationally (interconnect charges occur when different network operators transfer customer calls across their networks).

The best thing to do is to ignore any calls that you wouldn’t otherwise be expecting from unfamiliar country codes. Let them go to voicemail. Do not call the number back. If you do accidentally answer the call don’t worry. They can’t charge you! You will only be charged IF YOU CALL BACK.

So how does it work?

In order for mobile phone networks across different countries to communicate with each other, there is a system set up that processes the connections and also makes sure that any international charges are passed on to the person making the call, from the country the call was made to.

For example, if it costs you €2 to call a mobile number in South Africa, this system makes sure the right amount of charges are billed to you for that international connection time. Each time a call is bounced from one service provider to the other, the service provide charges the one before it thus the total cost will accumulate.

What’s happened in this case is the fraudsters would have compromised that system. They would have used a system called SIP connected through a software that automatically dials hundreds (if not thousands) of numbers per second. This is not done through a human intervention but through an automatic dialler. This system will call numbers which are fed to the system in a list. Through the SIP technology you can install a number from anywhere in the world so if the number that called you is showing Switzerland, most probably they would have automatically dialled you from a different country.

How will the fraudsters make money?

Fraudsters rely on you calling them back. Unless you call them back they will not make money! The way this scam works is that the number that called you is registered as a premium number. So once you call the number back, even if no one answers you, you will instantly be connected to an answering machine that might mimic the dialling tone (this may vary from one scam to another). The longer they keep you on the line, the more you’ll pay. These premium number can cost a fortune and it’s not unheard of that a call to one of these premium numbers will set you back around €15 per minute. Now multiply that by a thousand people that might fall to their trap and you can calculate how much money they will be making!

This scam is called ‘Wangiri’ which is a Japanese word meaning “one ring and cut”. The scam originated in Japan.

How did they get my number?

There’s two ways how they might have gotten your number.

a) The fraudsters would have researched and found out that all mobile phones in Malta start with 99, 79 or 77 (there are few different ones such as 98 as well). They will also easily know that Malta’s mobile numbers are 8 digits long. So with the use of excel they can generate all the numbers from 79000001 to 79999999 (and the same with 99, 77 etc). They will then feed these numbers into the dialler and let it do its magic by automatically calling hundreds of numbers per second for just a few seconds per call. This way however have its own drawbacks. Since there are many numbers between 000001 and 999999 that doesn’t exist it would waste a lot of time for the fraudsters because many numbers will be automatically rejected as “number do not exist” Hence why they would rather opt for option b.

b) This step involves a lot of data collection! Fraudsters might create free games on social media that entice you to play and requesting access to your profile. These are normally done through silly applications such as “see who your husband/wife will be”, “when will I die?”, “how will I die?” etc etc. These applications, although I’m not generalising that all of them are vehicles for fraudsters, might be used by fraudsters to collect working mobile numbers. Once they managed to collect thousands of numbers they will then feed them in the diallers to do the calls.


How can I ensure that I’m not a victim of this scam?

Very easy. Do not answer any calls from abroad that you’re not expecting (although by doing so you will nto be charged). Do not call back any missed call from such numbers (if you call YOU WILL BE charged) and if possible, be careful what applications you allow to access your social media profile. By being more careful you will definitely end up receiving less of these annoying calls.

I hope you found the above useful! I worked in Contact Centres for over 14 years and the above is mainly from the knowledge I gained in the industry. Obviously there might be other methods at work as well because the one thing that is always constant with these fraudsters is that they’re always trying to learn (and try) new methods!