Tokyo police have arrested a 17-year-old high school student from Osaka on suspicion of a large-scale cyberattack on the Kaikatsu Club internet cafe chain. The boy allegedly created a malicious program using ChatGPT, used it to access nearly 7.25 million customer records and, at least temporarily, disrupted the company’s services.
Tokyo police have arrested a 17-year-old high school student from Osaka on suspicion of a large-scale cyberattack on the Kaikatsu Club internet cafe chain. The boy allegedly created a malicious program using ChatGPT, used it to access nearly 7.25 million customer records and, at least temporarily, disrupted the company’s services.
According to police, the attack occurred at the end of January 2025 — a teenager tried to gain unauthorized access to the server of the official Kaikatsu Club application through a script he created.
An arrest warrant has been issued for the teenager on suspicion of violating the Computer Fraud Act and fraudulent obstruction of business.
The guy pleaded guilty. According to him, he «had fun finding vulnerabilities in systems.»
The attack affected user membership data — over 7 million records. According to an official statement from Kaikatsu Frontier (the network’s owner), the information may have included personal customer data; however, no abuse or mass leak has been confirmed.
The investigation found that to create the script that carried out the attack, the teenager turned to ChatGPT: when the code threw errors or something didn’t work, he «interrogated» the AI, received tips on how to bypass the protection, and changed the program. In this way, he managed to «bypass» the chatbot’s standard security guarantees.
