Keio ransomware attack disrupts group servers and Keio Plaza Hotel enquiries
Japan's Keio confirmed ransomware on its group servers on 26 Sept 2026 and cut its network. Keio Plaza Hotel warned of slow enquiry replies. No data leak is confirmed; trains are unaffected. Guests with bookings should confirm them with the hotel by phone.
If you have a booking at Keio Plaza Hotel Tokyo, confirm it by phone on +81-3-3344-0111 rather than relying on the website or reservation-site messages. Treat any unexpected email or call about your booking or payment as suspect until the hotel confirms it.
What’s happening
Keio Corporation, the Japanese rail and hospitality group, confirmed that ransomware hit its group servers in the early hours of 26 September 2026. It shut down its network to limit the damage and reported the attack to police. Keio Plaza Hotel Tokyo said some of its systems were still having problems and that replies to contact-form and reservation-site enquiries could be slower than usual, though it said hotel operations were not affected. Local media, cited by BleepingComputer, said payment systems were disrupted. Keio and the hotel say they are still investigating how the attackers got in, how far the damage goes and whether customer or business-partner information was taken. The hotel says it has not confirmed any leak. Train services were not affected. BleepingComputer found no ransomware group claiming the attack as of 28 September. The number of affected guests has not been disclosed, and no later official update was found. Status: ongoing.
- What
- Breach
- Affects
- Keio Corporation group servers and Keio Plaza Hotel Tokyo
- Fixed in
- Nothing to patch
- Since
- 26 Sept 2026
- Closed
- 28 Sept 2026
Timeline
- UpdateNothing to patch
BleepingComputer reported that Keio shut down its network and reported the attack to police. Keio was still working out whether customer or business-partner information was accessed. Local media said payment systems were disrupted. No ransomware group had claimed the attack, and train operations were not affected.
- Made publicNothing to patch
After a system failure in the early hours, Keio Plaza Hotel confirmed a ransomware attack on its servers. It blocked external networks, worked with Keio Corporation, police and outside experts, and warned that contact-form and reservation-site enquiries could be slow. It said it had not confirmed any information leak.
Sources
- Keio Plaza Hotel: notice of ransomware attackKeio Plaza Hotel · 26 Sept 2026
- Japan's Keio confirms ransomware attack disrupted business systemsBleepingComputer · 28 Sept 2026