Response to Data Breaches from Unauthorized Access
Overview
Cases of unauthorized access to the information systems of businesses and others handling large volumes of personal information, and theft of data containing personal information, have been confirmed in succession. The National Cybersecurity Office of the Cabinet Secretariat has urged businesses and others to promptly consider thoroughly implementing measures, including at contractors. The Ministry of Internal Affairs and Communications also conveyed the same information to businesses under its jurisdiction and related organizations, and called for stronger cybersecurity measures under the leadership of management.
Key points
- Repeated cases of intrusions through unauthorized access and data theft have been confirmed at businesses and others handling large volumes of personal information.
- The alert identifies measures including addressing vulnerabilities, strengthening authentication functions, and preventing the misuse of leaked information, including at contractors.
- The Ministry of Internal Affairs and Communications conveyed the same information to businesses under its jurisdiction and related organizations, and called for stronger measures led by management.
Overview
Repeated cases have been confirmed in which information systems of businesses and others handling large volumes of personal information were breached through unauthorized access, and data containing personal information was stolen.
The notice is dated October 9, 2026. The National Cybersecurity Office of the Cabinet Secretariat issued an alert to businesses and others, and the Ministry of Internal Affairs and Communications conveyed the same information to businesses under its jurisdiction and related organizations.
Impact
Businesses are being urged to further strengthen measures under the leadership of management. Particular caution is urged for businesses that hold large volumes of personal information or handle sensitive information.
Details
Recommended measures include promptly addressing vulnerabilities, strengthening authentication functions through multi-factor authentication and similar methods, and preventing the misuse of leaked information. Businesses and others are urged to promptly consider thoroughly implementing measures, including at contractors.
As reference information, the notice points to alerts from the Personal Information Protection Commission and JPCERT/CC.