An increasing number of Japanese companies have been hit by cyberattacks that disrupt online services and force firms to pay compensation to affected customers. The scale of the incidents has prompted the Tokyo government to take steps to strengthen national cybersecurity defenses.
Key corporate responses
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GMO Internet Group, one of Japan's leading online financial service providers, announced it will compensate customers affected by a cyberattack on its foreign exchange trading platform. CEO Kumagai Maszatosi said in a Sunday blog post that each affected customer will receive 5,000 yen (about $32) and will be offered free alternative services for six months. The company said it cannot yet precisely estimate the total cost of compensation payments.
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Park24, which operates the Times car-sharing service, said on Friday that an information leak would result in a 3,000-yen compensation payment per customer and an extraordinary loss of 5.5 billion yen overall for compensation and system recovery. The company also said it will stop retaining copies of customers' identity documents after completing registration checks.
Nature of the attacks and corporate handling
GMO said the attackers demanded a ransom and threatened to publish customer data; the company refused to pay and is cooperating with the police to mitigate the incident. Kumagai acknowledged that the company's ethical hackers had previously identified security weaknesses, but that the company's response was insufficient in depth and speed. Following the announcement, GMO's share price fell about 15%, sliding to a four-month low.
Government action and the role of AI
On Friday, the Japanese government announced the establishment of a cybersecurity unit that will use AI‑simulated attacks to identify vulnerabilities in IT systems. The move was prompted in part by critical security flaws discovered in the PHP programming language, which have disrupted government and corporate websites worldwide — including in Japan and Europe — and triggered waves of attacks.
Kumagai urged the government to activate the active cyberdefense system introduced earlier this year, a capability that reportedly could include taking down hostile servers.
Incident numbers and expert warnings
According to TrendAI, 723 cybersecurity incidents were recorded through October 20, 2026, surpassing the total number of incidents for 2024 and 2025. Experts warn that artificial intelligence has dramatically accelerated cybercrime, making processes from automated vulnerability scanning to phishing campaign development cheaper and harder to detect.
Aiszava Sóicsi, an analyst at IwaiCosmo Securities, said necessary upgrades to security systems will impose significant additional costs on companies.
Why this matters
The recent incidents expose both corporate and governmental vulnerabilities and illustrate how attackers are becoming more sophisticated, partly due to the availability of AI tools. Compensation payouts, recovery expenses and stepped-up government measures indicate that improving cybersecurity and data-handling practices has become an urgent priority for Japan's businesses.
This article was prepared with assistance from an AI tool; a journalist edited and verified the final content.
