The Nippon Medical School Musashi Kosugi Hospital in Kawasaki City announced on the 13th that a ransomware attack on their medical information system resulted in the leak of personal details for around 10,000 patients. The leaked data includes names, genders, addresses, phone numbers, birth dates, and patient IDs, but does not comprise information on medical conditions or credit card details. Despite the attack, the hospital's electronic medical records appear to be unaffected, and patient services such as outpatient care, hospital admissions, and emergency care are continuing as normal.

The breach was discovered on the 9th when the nurse call system began malfunctioning, leading to the identification of a ransomware attack on the server associated with it. The hospital reported the incident to the Ministry of Education and the Ministry of Health, Labor and Welfare. By the 11th, they confirmed the personal information had been leaked on a site believed to belong to the attackers. Investigations indicated that the attack was facilitated through a VPN device connected to the hospital's network, suggesting that a weak password may have been the entry point, which raises concerns about further potential leaks.

The attackers demanded a ransom of $100 million but the hospital has stated it will not comply with such demands. A report has been filed with the Kanagawa Prefectural Police. As of the 13th, the nurse call system remains partially inoperable, prompting the hospital to increase nursing staff and enhance patient monitoring. Hospital director Nobuhiko Taniai expressed his apologies to patients and their families and emphasized the need for thorough investigations and stronger measures to prevent future incidents, while also pledging to share the information with other hospitals to strengthen overall cyber defenses.