Keio Corporation hit by ransomware attack
Incident
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Keio Corporation confirmed a ransomware attack that disrupted sales systems at some group companies and forced the operator to disconnect systems from the internet. Railway operations were not affected, but police are still examining whether business information or customer data was leaked. The incident leaves a major Tokyo-region railway operator managing intrusion fallout while core transport services stayed online.
Timeline
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29.09.2026 12:45 2 articles · 2h ago
Ransomware attack disrupts Keio Corporation sales systems
Exploitation ObservedOn September 26, 2026, Keio Corporation said a ransomware attack struck its environment and caused disruptions in the sales systems of certain group companies. The company disconnected systems from the internet, and the Keio Plaza Hotel was among the businesses affected, while railway operations were not impacted.
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- Japanese Railway Operators Hit with Weekend Cyber Attacks — www.infosecurity-magazine.com — 29.09.2026 12:45
- Japanese Railway Operators Hit with Weekend Cyber Attacks — www.infosecurity-magazine.com — 29.09.2026 12:45
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29.09.2026 12:45 1 articles · 2h ago
Keio Corporation continues investigating possible data leakage
Initial DisclosureOn September 29, 2026, Keio Corporation said police were investigating whether confidential business information or customer data had been leaked after the ransomware attack. The company said it had not confirmed any data leakage at that time, and it warned that responses to inquiries through its official website and reservation sites could take longer than usual.
Show sources
- Japanese Railway Operators Hit with Weekend Cyber Attacks — www.infosecurity-magazine.com — 29.09.2026 12:45