A Swiss tele­phone number – yet trustworthy?

Many tele­phone users are not aware that the tele­phone number dis­played for a call isn’t nec­es­sarily cor­rect. This is how to pro­tect yourself.

Tele­phone users have become used to a caller’s number always being dis­played for every call they receive. This is a long­standing myth: If a Swiss number is dis­played for a call, this call orig­i­nates in Switzer­land and should cer­tainly be con­sid­ered trust­worthy. Many people are not aware though that a number can easily be faked.

Unlike Switzer­land, where tele­phone com­pa­nies are reg­u­lated by BAKOM, users of some for­eign, non-reg­u­lated tele­phone net­works can transmit any caller number they like. And you can also call into the Swiss land­line net­work this way. All num­bers, even if they have poten­tially been manip­u­lated by an attacker, are passed on unchecked and dis­played on your tele­phone dis­play. The use of faked Swiss tele­phone num­bers is a common prac­tice used by crim­i­nals to build up trust in users. In addi­tion, there are also some call cen­tres with Swiss num­bers actu­ally oper­ating abroad (source: NCSC).

Fur­ther infor­ma­tion can be found in our article on “Fraud­u­lent sup­port calls».