Sony ISP Subsidiary Data Breach Exposes 2.5 Million Customer Records
A significant data breach at Sony's internet service provider subsidiaries has compromised personal information of over two million customers.
A substantial data breach at Sony's internet service provider subsidiaries, So-net and Plala, has exposed personal information belonging to approximately 2.5 million customers in Japan. The incident, which occurred on October 19, 2026, was discovered four days later, prompting swift action from the company to address the security lapse 12.
The stolen data encompassed a wide range of personal identifiers, including names, dates of birth, genders, phone numbers, email addresses, user IDs, and internet connection IDs. This extensive collection of sensitive information underscores the potential impact on affected individuals, though fortunately, no credit card data was among the compromised records 12.
So-net, one of Sony’s internet service providers, took immediate steps to protect its users by resetting the passwords for the impacted email accounts on October 27, 2026. Additionally, sixteen records containing bank account details were leaked, highlighting the need for vigilance among the affected customers 1.
The cause of the breach has been attributed to unauthorized access by a third party, with an ongoing investigation aiming to uncover more details about the incident. Notably, NTT Docomo, which utilizes Sony Network Communications for its Docomo Hikari services, also informed its customers about the breach, indicating the widespread nature of the issue 12.
As of October 27th, there had been no reported misuse of the exposed data, providing some reassurance to the affected individuals. However, the timing of this breach coincides with a series of cyberattacks targeting Japanese companies and providers since the start of the year, suggesting a broader trend in cybersecurity threats within the region 2.
In response to these increased risks, the Japanese government convened urgent meetings to devise strategies for addressing the growing number of data breaches. These actions reflect the heightened awareness and concern surrounding digital security in Japan 2.
What we know
- Hackers stole personal information from So-net and Plala internet subscribers in Japan 12
- The attack happened on October 19, 2026, and was noticed on October 23, 2026 12
- Stolen information included names, dates of birth, gender, phone numbers, email addresses, user IDs, and internet connection IDs 12
- About 2.14 million records belonged to So-net subscribers and 443,000 to Plala subscribers 12
- So-net reset the passwords for the impacted email addresses on October 27, 2026 1
- Sixteen records containing bank account details were leaked, but no credit card data was involved 1
- Cause of the breach is listed as unauthorized access by a third party; investigation is ongoing 1
- NTT Docomo also notified its customers about the breach 2
- No misuse of the exposed data had been confirmed as of October 27th 2
- Multiple cyberattacks targeting Japanese companies and providers have occurred since the beginning of the year 2
- Japanese government held urgent meetings to plan responses to the recent increase in data breaches 2
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Verification report
- confirmed
Hackers stole personal information from So-net and Plala internet subscribers in Japan.
85% · supported by 2 - confirmed
The attack occurred on October 19, 2026, and was noticed on October 23, 2026.
85% · supported by 2 - confirmed
The stolen information included names, dates of birth, gender, phone numbers, email addresses, user IDs, and internet connection IDs.
85% · supported by 2 - confirmed
About 2.14 million records belonged to So-net subscribers and 443,000 to Plala subscribers.
85% · supported by 2 - likely
So-net reset the passwords for the impacted email addresses on October 27, 2026.
71% · supported by 1 - likely
Sixteen records containing bank account details were leaked, but no credit card data was involved.
71% · supported by 1 - likely
The cause of the breach is listed as unauthorized access by a third party; investigation is ongoing.
71% · supported by 1 - likely
NTT Docomo, which uses Sony Network Communications for its Docomo Hikari services, also notified its customers about the breach.
71% · supported by 1 - likely
As of October 27th, no misuse of the exposed data had been confirmed.
71% · supported by 1 - likely
Multiple cyberattacks targeting Japanese companies and providers have occurred since the beginning of the year.
71% · supported by 1 - likely
Japanese government held urgent meetings to plan responses to the recent increase in data breaches.
71% · supported by 1 - unverified
Nearly 2.6 million records were impacted by the data theft.
50% · supported by 1, contradicted by 1 - unverified
Around 293,000 records related to people who left the services in March 2026 or later.
50% · supported by 1, contradicted by 1 - unverified
Approximately 54,000 email addresses and their passwords were stolen from four additional mail services.
50% · supported by 1, contradicted by 1 - unverified
Sony Network Communications experienced a data breach compromising around 2.5 million records.
50% · supported by 1, contradicted by 1 - unverified
The breached data included full names, phone numbers, email addresses, user IDs, dates of birth, gender, and internet connection IDs for 2,585,481 customers.
50% · supported by 1, contradicted by 1 - unverified
Additional 54,401 email addresses and associated account passwords were exposed.
50% · supported by 1, contradicted by 1 - unverified
The affected records consist of 2,141,986 So-net entries and 443,495 plala (S Course) records.
50% · supported by 1, contradicted by 1
Sources & references
- SecurityWeek — Hackers Steal 2.6 Million Records From Sony’s Japanese ISP So-net
- BleepingComputer — Sony ISP subsidiary data breach exposes 2.5 million customer records
