A cascade of cyberattacks has hit Japanese companies over the past few weeks, prompting the government to call for security checks as AI tools lower the barriers to large-scale hacking.

Data from cybersecurity company Trend Micro shows a higher than usual number of Japanese organizations reported breaches in September. Thirteen were reported on a single day, the most this year. Reports have continued to flow in, hitting household names from SoftBank Corp. to Daiwa Securities, one of the country’s largest brokerages.

“Although the recent cyberattacks seemingly aim at stealing personal information rather than causing disruption, some actors could try to identify the threshold of Japanese active cyber defense,” said Mihoko Matsubara, Chief Cybersecurity Strategist at NTT Corp. “As a result, Japan may likely start to see more disruptive cyberattacks.”

Finance Minister Satsuki Katayama on Friday urged financial institutions to review their cybersecurity measures, while the Financial Services Agency also called for checks, including into third-party risks, and extra precautions when verifying users’ identity online.

The latest onslaught comes as AI tools that enable attacks are proliferating. According to Gambit Security, tools used to gain credit card details from e-commerce operators this summer cost an average of about $25.46 per strike. The performance of open-weight AI models, which can be downloaded for free, is also improving. Yoji Watanabe, chief technology officer at Cyber Security Cloud, said cyberattacks are becoming something that “even amateurs can carry out.”

The company’s analysis of unauthorized-access logs suggests AI may be being used to manage and control multiple attack tools.

Humans make the judgments while leaving “the small, tedious tasks to AI,” Watanabe said, adding that signs of this kind have been increasing since September. An outcry came after Times, one of Japan’s largest car-rental operators, suffered a data leak affecting 6.6 million members, including information from some drivers’ licenses. Research workers at the Japan Atomic Energy Agency had government-issued IDs exposed, while cloud storage service Rakuten Drive identified a breach where photos and documents belonging to about 15,000 accounts were accessed.

While many of the intrusions have been data breaches, organizations are also being hit with ransomware and supply chain attacks. Among Wednesday’s victims was SoftBank Corp. unit IDC Frontier, which said it had been the subject of a ransomware attack. The incident has caused disruptions at a number of its client companies.

The breaches in Japan come amid an apparent worldwide rise in such activity. Organizations globally were subject to an average of 2,803 cyber incidents a week in September, according to cyber security firm Check Point — 16% higher than August and 48% more than a year earlier.

South Korea is investigating AI use in a recent spate of cyberattacks on banks. Analysis by CrowdStrike suspects the perpetrator of using Chinese-developed agentic tool ARTEX alongside large language models.

The memory of two major ransomware incidents in 2025 — one of which disrupted supplies of beer from beverage giant Asahi Group — is still fresh. A member of hacker group Qilin, which claimed responsibility for the Asahi attack, was detained and extradited to Germany last week, several Japanese media outlets reported.

Ninety Japanese organizations suffered ransomware attacks in the first half of 2026, according to a report by Cisco Talos. The report found traces in Python scripts that suggest Qilin is using generative AI to amplify its capabilities.

“Japan has one of the worst computer security systems in the world,” Qilin said in comments to local media JNN this week. “This is why the number of attacks on companies and government agencies in Japan may increase. This is not a threat, but our expert opinion.”