Handset security developers have recorded an upturn in smartphones becoming infected by trojans that call premium rate lines leaving victims with a big bill. These dialler trojans - last seen in the forgotten days of dialup landline modems, are becoming increasingly popular with criminals looking to take advantage of new technology by reusing old, but profitable, scams.
According to the software firm CA, instead of the old-fashioned approach of dialling international numbers, these new smartphone diallers call premium rate numbers or send high rate SMS messages. Many diallers, including the Swapi.B software, are contracted from porn sites which disguise themselves as software, video clips or helper programs, said the company.
Mikko Hypponen, head of research at handset security with F-Secure, said diallers sent messages or rang many different numbers, including legitimate ones. "The trojan can place calls to, say, 100 different premium-rate numbers, only one of which is his own number," said Hypponen.
To make matters more difficult, some of the premium rate services have been crafted by the criminals as hard to shut down. "How would you fight this? Shut down all the numbers, including the innocent ones?" said Hypponen,
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BBC News
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