Cyber Incident Victim: Uji Hospital
Date:
Jan 2023
Location:
Japan
Summary
A ransomware attack targeted Uji Hospital, resulting in unauthorized system encryption and a ransom demand. The incident involved external data communication post-attack, indicating potential exfiltration of personal information including names and contact details of patients, current and former staff. While no confirmed misuse of data was identified at the time of disclosure, the hospital acknowledged it could not definitively rule out information leakage. The organization established a dedicated response channel and issued apologies to affected parties.
| CIA Posture | Motives | Tactics, Techniques & Procedures |
|---|---|---|
| Available to members | 1 motive | 1 technique |
| Threat Actors | Type | Location |
|---|---|---|
| 0 actors | Available to members | Available to members |
Description
On January 6, 2023, Uji Hospital operated by the Ajirigi Kai Social Welfare Corporation experienced a ransomware attack compromising its servers. Attackers encrypted hospital systems and issued financial demands. The hospital engaged external cybersecurity experts to investigate, revealing evidence of external data communications from the compromised servers following the attack. This communication pattern indicated potential unauthorized data exfiltration, though investigators could not definitively confirm data theft. The compromised information potentially included personal details of current and former patients, active employees, and retired staff members—specifically names and contact information. No clinical records or financial data were explicitly mentioned as compromised in available disclosures.
The hospital publicly disclosed the incident on June 12, 2023, acknowledging it could not conclusively rule out data leakage due to the detected external communications. While no confirmed cases of data misuse were identified by the disclosure date, the organization established a dedicated response center for inquiries and notifications. Formal apologies were issued to affected individuals and stakeholders. The ransomware’s specific variant and initial attack vector were not disclosed in public statements. Containment measures focused on forensic analysis rather than system restoration details, with no reference to ransom payment or data decryption success in available reports.