UPDATER (Minna Denryoku): its file server was infected with ransomware and information on customers and others may have leaked

1. 2022-09-18

   Late in the evening, ransomware was found on the file server. [1]

2. 2022-09-19

   It cut the network and set up a response headquarters. [1]

3. 2022-09-21

   At 19:00 it confirmed that customer information may have leaked. [1]

4. 2022-09-22

   It reported to the Personal Information Protection Commission and the Metropolitan Police Department, and announced the case. [1]

5. 2022-10-17

   A second report listed the groups whose information may have leaked. [2]

6. 2022-11-21

   A third report gave the results. The investigation by an outside specialist firm finished and found a ransomware infection caused by an external cyberattack. [3]

The information that may have leaked covers individual and corporate customers, power generators and partners, customers of contractors, shareholders and employees, plus later-added staff of contractors, event participants, applicants and campaign respondents. For customers paying by direct debit it includes bank account information. It holds no credit card data. The electricity supply is not affected. The number of people has not been published. [1] [2]

Monitoring by the specialist firm found no sign that the information that may have leaked was made public, and no trace pointing to misuse. There is no effect on the power supply or operations. It will rebuild its information security setup, introduce security diagnostics and train all staff. [3]