Sony Network Communications has disclosed a data breach exposing more than 2.58 million customer records following unauthorized access to its So-net membership database.
The incident also compromised passwords for 54,401 email addresses across four email services.
According to the company’s announcement, the intrusion occurred on October 19 but was discovered on October 23. Sony then shut down the affected server and blocked communications from the source of the unauthorized access.
The following day, an investigation confirmed that personal information had leaked and identified the affected data categories and record counts.
Sony Network Communications is a Sony Group company that provides consumer internet services in Japan, including So-net and NURO, as well as corporate technology services. The company says it has not identified information leaks affecting NURO or services outside those specified in its disclosure.
Customer details and email passwords exposed
The largest affected dataset contains 2,141,986 So-net membership records, comprising 1,869,771 current members and 272,215 former members who canceled from March 2026 onward.
A further 443,495 records concern plala (S Course) customers, including 422,365 current members and 21,130 former members.
Both datasets exposed names, phone numbers, email addresses, user IDs, dates of birth, gender, and internet connection IDs. Sony says passwords associated with these membership records were not leaked.
However, email addresses and their corresponding email passwords were exposed for customers using four specific services:
- Mail Service (G): 24,655 addresses
- A-Box additional mailboxes: 17,672 addresses
- So-net VAIO Mail: 7,005 addresses
- PostPet Mail Account Service: 5,069 addresses
These 54,401 email addresses belong to current or former So-net members in the affected population and should not be counted as additional customers beyond the membership totals. Sony has not disclosed how the compromised email passwords were stored.
The breach also exposed 16 bank account records containing financial institution and branch details, account types, account numbers, and account holder names. Sony says it does not hold bank account PINs, and no plala (S Course) customers were affected by this portion of the leak.
No credit card information was included in any of the disclosed data categories. Former members who canceled by the end of February 2026 were not included in the affected membership and email datasets.
Password resets and customer warnings
Sony reset the compromised email passwords on October 27 to prevent further harm. Affected customers must set new passwords through the official So-net My Page portal.
The company has reported the incident to Japan’s Personal Information Protection Commission and is continuing to investigate the intrusion method and full impact.
As of October 27, Sony said it had not identified subsequent harm arising from the breach, but warned that the exposed information could be used for suspicious communications.
Customers should access the password-reset portal directly and treat unexpected emails, text messages, and calls with caution, avoiding links and attachments in suspicious messages.
Sony Network Communications has disclosed a data breach exposing more than 2.58 million customer records following unauthorized access to its So-net membership database.
The incident also compromised passwords for 54,401 email addresses across four email services.
According to the company’s announcement, the intrusion occurred on October 19 but was discovered on October 23. Sony then shut down the affected server and blocked communications from the source of the unauthorized access.
The following day, an investigation confirmed that personal information had leaked and identified the affected data categories and record counts.
Sony Network Communications is a Sony Group company that provides consumer internet services in Japan, including So-net and NURO, as well as corporate technology services. The company says it has not identified information leaks affecting NURO or services outside those specified in its disclosure.
Customer details and email passwords exposed
The largest affected dataset contains 2,141,986 So-net membership records, comprising 1,869,771 current members and 272,215 former members who canceled from March 2026 onward.
A further 443,495 records concern plala (S Course) customers, including 422,365 current members and 21,130 former members.
Both datasets exposed names, phone numbers, email addresses, user IDs, dates of birth, gender, and internet connection IDs. Sony says passwords associated with these membership records were not leaked.
However, email addresses and their corresponding email passwords were exposed for customers using four specific services:
- Mail Service (G): 24,655 addresses
- A-Box additional mailboxes: 17,672 addresses
- So-net VAIO Mail: 7,005 addresses
- PostPet Mail Account Service: 5,069 addresses
These 54,401 email addresses belong to current or former So-net members in the affected population and should not be counted as additional customers beyond the membership totals. Sony has not disclosed how the compromised email passwords were stored.
The breach also exposed 16 bank account records containing financial institution and branch details, account types, account numbers, and account holder names. Sony says it does not hold bank account PINs, and no plala (S Course) customers were affected by this portion of the leak.
No credit card information was included in any of the disclosed data categories. Former members who canceled by the end of February 2026 were not included in the affected membership and email datasets.
Password resets and customer warnings
Sony reset the compromised email passwords on October 27 to prevent further harm. Affected customers must set new passwords through the official So-net My Page portal.
The company has reported the incident to Japan’s Personal Information Protection Commission and is continuing to investigate the intrusion method and full impact.
As of October 27, Sony said it had not identified subsequent harm arising from the breach, but warned that the exposed information could be used for suspicious communications.
Customers should access the password-reset portal directly and treat unexpected emails, text messages, and calls with caution, avoiding links and attachments in suspicious messages.
Leave a Reply