Cyberattacks expose millions of records in Japan and South Korea

Cyberattacks have exposed tens of millions of personal records in Japan and South Korea, The Straits Times reported in an article published Oct. 16.

The newspaper said Japan had more than 600 corporate cyberincidents by early October 2026, exceeding the full-year 2025 total, as attacks hit cloud providers, banks, retailers and public services.

Masaaki Taira, who chairs the ruling Liberal Democratic Party’s cybersecurity apparatus in Japan, called the escalation a “national cyberspace emergency” on Oct. 9, according to the article.

South Korean President Lee Jae Myung said artificial intelligence is reducing the skills needed to attack networks, warning that amateur hackers can “use AI to breach systems with ease even without specialised skills”.

Harumichi Yuasa, dean of the Graduate School of Governance Studies at Meiji University, said the recent incidents “appear to involve advanced AI technology systematically scanning for vulnerabilities and exploiting them to gain unauthorised access”.

The attacks have included ransomware, which locks computer systems until payment is demanded, and network intrusions aimed at stealing customer data. IDC Frontier, a SoftBank subsidiary that provides cloud and data-centre services, said on Oct. 7 that a ransomware attack disabled services for 495 corporate and municipal clients.

The IDC Frontier outage forced frozen-food distributor Nissui to halt shipments to 1,200 business partners and also affected websites for Ibaraki prefecture and its police headquarters, the article said. The case showed how one technology supplier can transmit operational risk across companies and public bodies.

Other Japanese breaches involved large consumer datasets. The article listed exposed records at SOURCENEXT, with 22.51 million customer records; Skyticket, with 14.64 million; Burger King, with 11.18 million; Yakiniku King, with 10.78 million; Big Echo, with 8.72 million; JR East, with 6.09 million; and Lawson, with 2.15 million.

On Oct. 16 alone, reported leaks included Yamato with 5.3 million records, Nikkei with 1.83 million, Yellow Hat with 1.8 million and FANCL with 780,000, according to The Straits Times. A breach affecting Park24’s Times Car rental service led to images of 1.6 million driver’s licences being offered on the dark web for as little as 20 yen each, the article said.

South Korea has also seen attacks on financial and religious institutions. The newspaper said Yoido Full Gospel Church and SaRang Church confirmed on Oct. 7 that they were investigating breaches that exposed hundreds of thousands of congregant records, including tithe and donation histories.

Between late September and early October, at least 16 financial institutions, including Shinhan Bank and KB Kookmin Bank, were hit by intrusions exposing roughly 100,000 customer contact and borrowing records, the article said.

The evidence presented in the article does not establish direct state involvement. Yuasa said there was “at present, no evidence suggesting direct nation-state involvement”, while adding that attackers are targeting organisations with large stores of personal data for sale on underground markets.

Both countries have passed new laws in response to recent breaches, but experts cited by the newspaper said the measures may not be enough as AI tools accelerate vulnerability scanning and outsourced vendors become single points of failure. Internal Affairs Minister Hisayuki Fujii said on Oct. 16 that local governments must “secure multiple means of transmitting disaster information to avoid reliance on one single provider”.

Source: News article, The Straits Times, Oct. 16, 2026.