The UK is to become the first country in Europe to ban SIM farms in a measure to assist in the protection of consumers.
SIM farms are electronic devices that are capable of simultaneously using many SIM cards (subscriber identity modules) to send SMS texts or phone calls in large numbers over the telecommunications network.

The aim of the UK government is to clamp down on the sending of scam calls or texts by fraudsters. So-called phishing messages can be used to lure recipients in giving away personal or financial information. Vodafone UK has reported it has blocked more than 73 million suspicious texts in 2024 alone. The proposed legislation will assist is stemming the flow of these messages.

SIM farms can also be used to fraudulently drive traffic to a premium rate telephony service (PRS) run by the criminal. For example, the fraudster may automate very short calls from the SIM farm to victims which will not be picked up in time. Having noticed the “missed call”, people may make a call to the PRS through the SIM farm without realising it is charged at the premium (very high) rate.

In the past, SIM farms containing fraudulently obtained SIM cards were used by criminals to terminate international calls that bypassed the PTSN (public service telephone network) and so avoided high international call charges. The low cost service was advertised to potential users in other countries primarily through the sale of international calling cards. Of course, the widespread use of free VoIP services such as WhatsApp has now made that fraudulent activity redundant. But as always, criminals have moved on by exploiting advances in technology and services for new ways of defrauding the unwary.

PTT’s online course “Telecommunications systems security” explores ways of reducing the vulnerability of telecommunication systems and databases to security breaches and fraudulent misuse.