# Sony Network Communications Data Breach Exposes 2.5 Million Records A major cyberattack on Sony's ISP subsidiary compromises sensitive customer data and email credentials. - **Source:** [Latest from TechRadar](https://www.techradar.com/feeds.xml) - **Published:** 2026-10-29 - **Topic:** [Software & Engineering](https://brifing.si/c/engineering) - **Original article:** - **On Brifing:** https://brifing.si/s/48f52ab6-dd1a-43ec-9e45-21a7121d536e ## Breach Scope and Timeline Sony Network Communications confirmed a significant data breach affecting approximately 2.5 million users of its So-net ISP service. The unauthorized access occurred on October 19, 2026, and was detected four days later. The company immediately shut down the compromised server and blocked the source of the intrusion to prevent further data exfiltration. ## Exposed Personal Information The attackers accessed a total of 2,141,986 sensitive records belonging to current and former members. Compromised data includes names, phone numbers, email addresses, user IDs, dates of birth, and gender information. While general passwords remained secure, some users of specific email services had their email passwords stolen during this security incident. ## Impact on NTT Docomo The breach extended to NTT Docomo, which utilizes Sony’s underlying infrastructure for its Hikari service. Over 440,000 records from the plala S Course were compromised, affecting both active clients and those who canceled subscriptions since May 2026. NTT Docomo has issued warnings urging customers to remain vigilant against potential phishing attempts and suspicious communications. ## Specific Email Service Exposure Beyond general ISP data, the attackers targeted specific mailbox services including Email Service G, A-Box, So-net VAIO Mail, and PostPet Mail. Records affected include 24,655 addresses for Email Service G and 17,672 for A-Box. Smaller numbers were impacted across other services, with the company confirming that only users active since March 2026 face risks. ## Banking Data Compromise A small subset of 16 records contained sensitive banking information, including bank codes, branch names, and account numbers. Sony confirmed that no bank account PINs were stored on their systems, ensuring those credentials remained safe. The company is currently in the process of individually contacting the specific customers affected by this financial data exposure. ## Response and Regulatory Compliance Sony Network Communications has notified Japan’s Personal Information Protection Commission and relevant law enforcement agencies regarding the incident. The company is conducting a thorough investigation to determine the exact methods used by the attackers. No hacking group has claimed responsibility, and the stolen data has not yet surfaced on the dark web. ## Context of Japanese Cyberattacks This incident follows a recent security alert from the Japanese internet giant GMO Group, which advised customers to scan devices and disconnect from the internet due to potential threats. The proximity of these two events highlights a broader trend of increased cyber activity targeting major Japanese technology and telecommunications infrastructure providers this month. ## Security Implications for Users The primary risk for affected customers remains phishing and fraud, as attackers now possess verified contact details and email credentials. Users are strongly advised to avoid clicking suspicious links, opening attachments, or responding to unsolicited calls. Vigilance regarding account security and monitoring for unauthorized activity is critical for all impacted So-net and Docomo users. ## Sources covering this story - https://www.techradar.com/pro/security/data-breach-at-sony-isp-subsidiary-exposes-2-5-million-customer-records-as-japan-hit-with-another-major-cyberattack — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._