Phones near a blaster can be forced to connect to its illegitimate 4G signals, before the blaster pushes devices to downgrade to the less secure 2G signal. “The 2G fake base station is then used to send (blast) malicious SMSes to the mobile phones initially captured by the 4G false base station,” Mc Daid says. “The whole process—4G capture, downgrade to 2G, sending of SMS and release—can take less than 10 seconds,” Mc Daid explains. It’s something people who receive the messages may not even notice.

“Once phones are connected to these fake cell sites, they can spoof any sender ID or number to send the scam message.”

Yomna Nasser, a software engineer at Android, says people can stop their phones connecting to 2G networks in their settings. “Once enabled, your device will no longer scan for or connect to 2G cell towers,” Nasser says, adding the only exception is if an emergency call is being made and 3G, 4G and 5G are not available. Android’s Advanced Protection mode will also disable 2G automatically on some newer phones. Apple did not answer WIRED’s request for comment by the time of publication, although its Lockdown Mode will disable 2G connections.