Security on SIM

“Why would somebody want to take the SIM out and use it?” was a question I was asked by somebody who was not a Mobius customer.

“Because it is free.” Was the simple answer. It still seemed a surprise despite the fact that he had been presented with an overage bill of just under £130,000 for one month. Although this bill was spread over about 20 SIMs it still represents the largest fraudulent use I have personally seen.

Any discussion of Security should start with the SIM and yet it is generally overlooked. There is a great deal of investment in Software to restrict the sites a user can visit, apps they can download or films they can stream. But all the end user has to do is take the SIM out and put it in something else and they have sidestepped all that security.

Some companies go to great lengths to physically isolate the SIM from a hostile outside world. But we have seen a ticket machine with 17 screws between the user and the SIM stripped down in less than half an hour of first being turned on. Once people know there is a free SIM to be had it is amazing the lengths people will go to. Well, it is free!

In Johannesburg the story goes that someone ran over a Smart Traffic Light System (or Robot as they are known locally) and spotted that it was a SIM controlling data to the traffic lights. Within weeks all the SIMs had been stripped out crippling the traffic lights and racking up cost for the city.

Mobius believes that every SIM is a blank cheque which is why we offer to tie them down for our customers. You choose the level of security that’s appropriate;

Can’t visit certain websites, or can only visit the ones you want.

Can only visit your server or can’t access the internet at all

Will only work in your hardware or even only work in that particular device

And that security can be flexible. If you want a SIM that will work entirely offnet on a private network with fixed IP but needs to access the BBC News tickertape every 15 minutes we can build that for you. There are also the simple things like;


  • Remove Voice or set for incoming Voice only

  • Remove text
  • And all of that security is on the SIM, no special software or hardware required. And it follows the SIM wherever it goes. So please take security seriously, contact Mobius at the usual address [email protected] and find out how we can help. 

    Written by

    Douglas Gilmour

    Douglas formed Mobius in 2003 after twenty years’ experience in the Semiconductor industry. He was driven by the idea that airtime could be better and more secure.