Japanese Railway Operators

Keio's hospitality arm went down to ransomware in the early hours of September 26, 2026, dragging payment systems with it while train operations kept running. No group has claimed it, no entry point has been named, and Keio itself says it is still investigating whether customer or partner data went out the door. A railway and a hotel chain shared enough infrastructure that one attack could reach both; the operator built one network for two businesses and called the surviving half a success. Segmentation that actually separates a hotel's payment system from a group's core servers is not optional.