A Chinese national has been arrested in Japan for allegedly setting up a “fake base station” in Tokyo’s upscale Ginza district. This illegal device was reportedly used to send out interference signals, resulting in over 10,000 smartphones temporarily losing their network connection. Following this disruption, the suspect is accused of sending phishing text messages disguised as credit card notifications to steal sensitive financial information.
According to reports, the Tokyo Metropolitan Police apprehended the suspect, identified as 31-year-old Yu Haiyong, on November 9. He is alleged to have installed the unauthorized “fake base station” equipment inside a parked vehicle in Ginza on the afternoon of November 7. Without the proper permits, Yu reportedly emitted wireless communication waves that caused thousands of smartphones in the vicinity to enter a “no service” mode for about an hour. Yu has denied the charges, claiming he was unaware of the situation.
Authorities have indicated that the fake base station Yu set up mimicked the signals of legitimate telecommunications companies, deceiving smartphones into connecting to it. By exploiting the tendency of devices to latch onto stronger signals, the fake base station disrupted normal communication. This then allowed the device to send fraudulent messages, pretending to alert users about issues related to their credit cards.
From January 2025 to October 2026, 18 individuals, many of whom were Chinese tourists, reported receiving text messages in Chinese claiming that their credit card transactions had been suspended or that their cards may have been compromised. Those who clicked on the links provided in these messages and entered their credit card information subsequently faced unauthorized charges, amounting to an estimated loss of about 4 million yen.
Reports further revealed that the suspect appeared to have used a device known as an “IMSI Catcher” to interfere with standard 4G and 5G communications. This allowed him to leverage the weaker security protocols of the 2G network to send his phishing texts to users’ mobile phones.
In December 2024, users of the Japanese telecommunications company Docomo in areas such as Ginza and Shinjuku began experiencing unexplained signal losses. After conducting an investigation in January 2025 in collaboration with Japan’s Ministry of Internal Affairs and Communications, Docomo confirmed that these incidents were linked to illegal radio interference activities.
This case sheds light on the increasing sophistication of cybercrime, particularly as criminals find innovative ways to exploit technology for fraudulent purposes. The involvement of a fake base station represents a concerning trend that could jeopardize the safety and security of mobile communications and financial transactions. As authorities crack down on such illegal operations, the public is urged to remain vigilant against potential phishing scams, especially during travels abroad where the risk may be heightened.