Nippon Steel IT Subsidiary Hit by “Zero-Day Attack,” Causing Data Breach – Source: www.infosecurity-magazine.com

NS Solutions, an IT services provider owned by the Japanese conglomerate Nippon Steel, has confirmed that data from employees, partners and customers may have been leaked following a cyber-attack.

According to a statement published in Japanese on July 8, NS Solutions, also known as Nittetsu Solutions and Nippon Steel Solutions, detected unauthorized access to its internal network on March 7, 2025.

The company described the incident as a “zero-day attack” caused by the exploitation of an unknown software vulnerability in some network equipment, […]  which may have resulted in the leakage of personal and other sensitive information belonging to our customers, partners and employees.”

PII and Sensitive Data Exposed

This data could include the following:

• Customers: Name, company name, department, position, company address, business email address and phone number
• Partners (including former partners): Name and business email address, including company-provided domain addresses
• Employees (including former employees): Name, department, position and business email address

The company stated that there was no evidence of the leaked information being disseminated on social media or the dark web at the time of the announcement, nor had any secondary misuse of the data been confirmed.

However, the company’s spokesperson advised caution against unsolicited or suspicious calls and emails.

NS Solutions’ Internal Network Restored

NS Solutions confirmed that immediately after identifying the unauthorized access, the company took swift action to block all external connections to the compromised systems.

“We have implemented appropriate measures, including isolating and rebuilding affected systems, as well as strengthening exit controls and behavioral detection to mitigate residual risks,” said the company.

“Our internal network has been restored to a secure state.”

Additionally, NS Solutions has reported the incident to the police and the Personal Information Protection Commission and has been working closely with its business partners to implement necessary security measures.

It also said that it will notify affected individuals in accordance with Japan’s Act on the Protection of Personal Information (APPI).

Nippon Steel, the owner of NS Solutions, acquired its US counterpart, US Steel, for $14.9bn in June, 2025, despite President Donald Trump and his Democratic opponents voicing concerns during the 2024 US presidential election about the foreign acquisition of one of the last major steel producers in the country.

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