The Czech Telecommunications Office (ČTÚ) warns against fraudulent calls, so-called “wangiri,” in which an attacker briefly calls a domestic user from a foreign phone number. The return call then costs the caller a large sum of money.
“Currently, the most common calls are from numbers that begin with the +94 area code belonging to Sri Lanka. Fraudulent calls of this kind are usually from abroad, ” the ČTÚ warned on Wednesday.
Practically, the only defense against astronomical phone bills is, therefore, not to respond to such calls from foreign numbers. “Otherwise, they (users) risk being forced to pay the increased price of such calls, and since they make the call of their own free will, they can not rely too much on success in any complaint procedure,” the authorities explained.
Banking houses have also long warned against fraudulent calls. Attackers present themselves as bank representatives and try to extract internet banking login details from people under various pretexts and supposedly advantageous offers or, on the contrary, with false warnings.
In this context, banks warn that they never ask users for complete payment card details, internet banking login details or SMS authorization, passwords, and PINs as part of the verification or checking of outgoing transactions.