Vietnam’s Ministry of Information and Communications has warned the public about a plague of fake base transceiver stations that are used to spam mobile phones with dishonest SMS messages, reports Thương Trường and various other sources.
In late March two men were arrested by the Quang Nam Provincial Police (pictured below) for driving around an SMS blaster and using it to spam subscribers of Mobifone and Viettel within the provinces of Thua Thien Hue and Ho Chi Minh City. Per the police’s press announcement, the men used a device that connected to mobile phones within a 50m radius.
One suspect subsequently admitted to receiving a computer and two IMSI-catchers from a Chinese man who paid them to send SMS messages after explaining how to use the equipment. The purpose of the messages was to lure victims into a property scam. The arrestee claimed that he and his accomplice received over VND110mn (USD4,700) in total, at a rate of VND500,000 (USD21) for every 10,000 SMS messages. This implies that more than 2.2 million scam messages were sent using the two SMS blasters.
These IMSI-catcher scammers used similar methods to a rash of other criminal operations recently identified by Vietnamese law enforcement. The Ministry of Information and Communications told journalists at an April 6 press conference that eight separate IMSI-catcher cases have been detected across seven different Vietnamese provinces since the beginning of March 2023. Some of these SMS campaigns try to lure victims into entering their details into phishing websites designed to mimic respected institutions whilst others entice men into romance scams, sometimes using pornographic messages.
Many Vietnamese news organizations have reported a surge in complaints about romance scam messages. It appears that the use of the SMS blasters in densely-populated areas means that some phone users would receive identical SMS messages at several different times on the same day. The romance scams are so frequent that they are known by commonly-recurring names such as “da pho” and “bong hong”.
The risk of portable radio devices being used for these kinds of scams gained attention in the West when an IMSI-catcher was mistaken for a bomb by Parisian gendarmes in late December. Subsequent investigations discovered the same Paris gang also sent smishing messages using a second IMSI-catcher carried in an old ambulance. However, it is evident that Asian scammers have been using this kind of technology and technique for longer. Vietnamese news reports indicate this latest burst of fake BTS activity is an evolution of past scams but with technology that is now better and more readily available.
Based on past experience, it is safe to assume that most countries will wait until thousands of citizens have fallen victim to scams spread by portable SMS blasters before any effort is made to assemble the same kind of specialized law enforcement task forces that have reportedly been created in Vietnam and France. Instead of learning from the experiences of others, language barriers, arrogance and apathy will allow this criminal technique to spread globally. And once again, the public will be fed a cliché about fighting comms fraud being like a game of ‘whac a mole’ because law enforcement cannot anticipate what criminals will do next.
