We would like to inform our guests that a system disruption occurred in "DX Denwa MVcloud," the automated telephone response service used by Hotel Niwa Tokyo and provided by Media Links Co., Ltd. The disruption resulted from unauthorized third-party access, identified as a ransomware attack, targeting East Japan Region 1 of the cloud infrastructure operated by IDC Frontier Inc.
An investigation into the scope of the impact, the method of intrusion, and other relevant matters was conducted with the assistance of an external cybersecurity firm. According to an official announcement issued by IDC Frontier Inc. on October 14, 2026, no evidence was found that any data stored on the affected virtual servers had been accessed or transferred outside the affected environment. Based on these findings, IDC Frontier Inc. concluded that no data leakage to external parties had occurred.
We will continue to closely monitor the situation, gather relevant information, and take all necessary and appropriate measures.
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1. Overview
At approximately 3:40 a.m. on October 7, 2026, unauthorized access by a third party occurred within IDCF Cloud, a cloud service operated by IDC Frontier Inc. As the result, certain systems experienced service disruption. IDC Frontier Inc. subsequently conducted an investigation to determine the scope of the impact and whether any data had been compromised.
2. Personal Data That May Have Been Affected
Among the personal data managed by Hotel Niwa Tokyo within the affected cloud environment, the following information may have been affected:
・Telephone numbers
・Audio recordings of telephone inquiries made to Hotel Niwa Tokyo
At this time, there is no confirmed evidence that any of this personal information has been leaked to any third party.
3. Cause
The incident was resulted from unauthorized access by a third party to the cloud service infrastructure operated by IDC Frontier Inc. IDC Frontier Inc. In cooperation with an external cybersecurity firm, IDC Frontier Inc. investigated the intrusion route, access logs, authentication logs, operation logs, and other relevant records to assess the scope and impact of the incident.
4. Secondary Damage and Potential Impact
At this time, no evidence has been found indicating that the affected data was transferred outside the relevant environment. In addition, no unauthorized use of information or other secondary damage resulting from this incident has been confirmed.
Should any new material facts come to light, we will promptly provide further information.
5. Additional Information
Immediately after becoming aware of the incident, we began gathering information from the relevant service providers and have continued to confirm the security of the system and assess the scope of the impact.
According to the investigation conducted by the cloud service provider, no evidence was identified that data stored within the affected environment had been transferred outside that environment.
We will continue to work closely with the relevant organizations and service providers, take all appropriate measures, and make every effort to prevent similar incidents from occurring in the future.
Official Announcements
IDC Frontier Inc. - October 14, 2026
"Update No. 5: Progress of Investigation into the Service Disruption Caused by Unauthorized Access"
View the official announcement.
IDC Frontier Inc. - October 9, 2026
"Update No. 4: Response Structure for the Service Disruption Caused by Unauthorized Access"
View the official announcement.
IDC Frontier Inc. - October 8, 2026
"Update No. 3: Service Disruption Caused by Unauthorized Access to Certain Systems"
View the official announcement.
IDC Frontier Inc. - October 7, 2026
"Unauthorized Access to Certain Systems of Our Services"
View the official announcement.
The term "our" in the titles of the above announcements refers to IDC Frontier Inc.
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Contact
For any inquiries regarding this notice, please contact:
Hotel Niwa Tokyo
Email: stay＠hotelniwa.jp
