Such numbers are used in conjunction with malicious apps that reply to text messages and then delete confirmation messages so users end up paying vast sums to cybercriminals without realising. The Mobile Cybercriminal Underground Market report outlines some of the key businesses operating in this vast and sophisticated network.
A GSM modem can send out thousands of spam text messages every hour Spam devices It includes the selling of premium-rate phone numbers, which can be bought from 220,000 yuan (