Unauthorized access by a third party was confirmed at アルカディア, which operates a disaster information distribution service for municipalities, raising the possibility that up to approximately 313,600 records, including residents' email addresses, may have been leaked. The impact is expected to extend nationwide, and 36 municipalities have suspended disaster-prevention email distribution and other services.
アルカディア, which operates disaster information distribution services for municipalities, confirmed an incident suspected to involve unauthorized access by a third party on the afternoon of the 11th and took emergency measures in the early hours of the 12th to block the intrusion route. Subsequent investigation identified an external entry route, and from 11 a.m. on the 13th the company urgently suspended part of the service and part of its contact service for schools.
According to the Ministry of Internal Affairs and Communications, the information potentially leaked at this time primarily consists of residents' email addresses, with the number of affected records reaching a maximum of approximately 3.136 million. The impact has spread to municipalities across Japan, and as of 9 p.m. on the 13th, 36 municipalities had suspended disaster-prevention email distribution and other services.
The scope of the impact and whether any information was leaked are still under investigation, and approximately 800 municipalities use the SpeeCAN RAIDEN disaster information system. アルカディア said that it had identified and blocked the IP address of the source of the intrusion, but stated that it would wait for the facts to be clarified before disclosing the full extent of the damage.
Some municipalities have been required to secure alternative means of communication after suspending disaster-prevention email distribution, creating a need for early restoration. The company commented that it would promptly disclose any new facts as soon as they become known.