IDCF Cloud was infected with ransomware, reportedly making data recovery difficult in 4 zones of East Japan Region1 and affecting 495 companies and local governments. Some data, including data from JR East’s email distribution service, may have been exposed.
IDC Frontier, which provides IDCF Cloud, said that East Japan Region1 was encrypted by ransomware early on 7 October 2026. The affected service was its cloud service, and 495 companies and local governments were publicly reported to have been affected. To prevent further damage, the affected region was disconnected from the network and the management console was suspended.
Regarding the scope of the impact, data in the tesla, henry, pascal and joule zones of the East Japan Region is reportedly difficult to recover, and there may be no recovery route other than using backups held by individual customers. Meanwhile, no unauthorized access has been confirmed at this time in the radian, newton, East Japan 2/3 and West Japan 1 zones.
Among the affected companies, the View Card email distribution service associated with JR East may have had up to approximately 6.09 million records exposed. The company explained that names, addresses, telephone numbers and credit card information were not affected. JR Kyushu’s approximately 1.3 million member email addresses were also identified as being within the scope of the impact.
IDC Frontier said it will continue blocking East Japan Region1’s network and conducting security checks by region. The entry point for the incident and the attacker have yet to be identified. SoftBank is providing a contact point for customers’ backup migration and for starting or stopping virtual machines, while the investigation and recovery work are proceeding in coordination with the company.