Japanese law enforcement has arrested three teenagers for allegedly using ChatGPT and automated tools to fraudulently obtain mobile phone contracts through Rakuten Mobile Inc.‘s systems. The arrests, which took place in February 2025, involved male students aged 14, 15, and 16 who reportedly met through online gaming platforms. The case comes as Japan continues to strengthen its digital identity infrastructure and telecommunications security measures.
According to police reports, the suspects accessed Rakuten Mobile’s systems between May and August 2024 to create contracts under other individuals’ names. The 16-year-old high school student from Gifu Prefecture developed the primary program used for the unauthorized access. The incident reveals vulnerabilities in telecom authentication systems, despite Rakuten’s recent integration of advanced AI-powered security measures.
The investigation revealed that the suspects employed an automated program to attempt system logins using ID and password combinations, which were allegedly purchased through the Telegram messaging platform. Police discovered approximately 3.3 billion sets of login credentials on the suspects’ computers. The practice of account takeover fraud has become increasingly common, with cybercriminals exploiting automated tools to bypass traditional authentication methods.
The group allegedly sold at least 2,500 illegally acquired mobile lines, generating approximately 7.5 million yen in cryptocurrency revenue. The 15-year-old junior high school student from Shiga Prefecture, identified as the alleged mastermind, stated to police that his motivation was to gain social media attention. The other two suspects indicated financial gain as their primary motivation.
The proceeds from the operation were reportedly used to purchase gaming consoles and participate in online gambling activities. The arrests were carried out between February 3 and 25, 2025. The case shares characteristics with recent telecommunications fraud incidents worldwide, where criminals have exploited gaps in SIM registration and verification systems.
The incident represents one of the first documented cases in Japan where ChatGPT was used as a tool in telecommunications fraud, highlighting emerging challenges in cybersecurity as AI tools become more accessible. The case emerges as Japanese authorities have been implementing stricter digital identity verification measures across various sectors, including the recent integration of health insurance systems with the national digital ID framework.
Sources: Marketscreener, VNExpress, Japan Today
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