Sony Life Insurance said on October 28 that unauthorized access to its policyholder website exposed the personal data of about 385,000 people insured under Medicare Life Insurance policies that Sony Life handles as an agency.
The breached systems include Sony Life's Okyakusama WEB Service portal. Names, dates of birth, gender, addresses, phone numbers, policy numbers and contract details were exposed.
My Number identifiers, credit card details and bank account information used for premium payments were not among the data, the insurer said.
Sony Life detected the unauthorized access on October 27. It cut off outside access to the affected systems and suspended the related services. The company said it is still investigating and working to identify the cause and the full scope of the breach.
As of October 28, Sony Life had found no evidence that the customer data had been misused. It has reported the breach to the Financial Services Agency and will contact affected customers in turn.
The disclosure follows a run of data breaches at Japanese companies, including an attack on a GMO-linked single sign-on service that exposed files for 45,000 people and a breach at the cosmetics review site @cosme affecting about 3 million members.