Japan-based IDC Frontier says a ransomware attack has disrupted parts of its IDCF Cloud platform, leaving virtual servers stopped and unrestartable in several East Japan Region 1 zones.

In a third update published October 8, the SoftBank Group digital infrastructure company said the incident began around 3:40 a.m. Japan time on October 7 and remained ongoing. The affected scope is listed as portions of East Japan Region 1, including the tesla, henry, pascal, and joule zones.

IDC Frontier said 495 companies and local governments using IDCF Cloud were affected. The company attributed the disruption to unauthorized third-party access described as a ransomware attack, while adding that the full impact and intrusion path remain under investigation.

The most significant warning for hosted workloads is data recovery. IDC Frontier said customer data stored in the affected zones is expected to be difficult to extract or restore, and that, based on its current view, recovery is only possible from backups customers hold themselves. Affected customers are being guided to rebuild in separate environments and restore from their own backups.

The company also said no unauthorized access had been confirmed in other East Japan Region 1 zones, East Japan Regions 2 and 3, or West Japan Region 1 as of the update, but it advised customers in those areas to take their own backups. Because the customer management console is stopped, IDC Frontier said it is manually handling some customer requests, including virtual server start and stop operations.

Why hosting teams should watch this

The incident is a blunt reminder that cloud availability and cloud durability are separate risks. Snapshots and backups kept only inside the same provider, region, account, or control-plane dependency may not be enough when ransomware, account compromise, or provider-side isolation steps affect the recovery path.

For site operators and hosting teams, the practical checklist is familiar but urgent: keep tested offline or cross-provider backups, document rebuild steps for critical applications, verify DNS and traffic-failover procedures, and rehearse restoring a site without access to the original cloud console.

Source: IDC Frontier incident update. Independent coverage: BleepingComputer.