Canadian authorities have arrested three men for operating an “SMS blaster” device that pretends to be a cellular tower to send phishing texts to nearby phones.

Such tools trick devices into connecting to them by emitting signals that mimic a legitimate tower. Mobile phones in its range automatically link to them as there is stronger reception.

Once the connection is established, the operators of these rogue cellular base stations can push SMS messages directly to connected devices, which appear to come from trusted entities such as banks or the government.