Advantest Corporation disclosed that its corporate network has been targeted in a ransomware attack that may have affected customer or employee data.

Preliminary investigation results revealed that an intruder gained access to certain parts of the company’s network on February 15.

Tokyo-based Advantest is a global leader in testing equipment for semiconductors, measuring instruments, digital consumer products, and wireless communications equipment.

The company employs 7,600 people, has an annual revenue of more than $5 billion, and a market capitalization of $120 billion.

On February 15, the firm detected unusual activity in its IT environment, prompting a response in accordance with incident response protocols, including the isolation of affected systems.

As part of its response, the company contracted third-party cybersecurity specialists to help isolate the threat and investigate its impact.

“Preliminary findings appear to indicate that an unauthorized third party may have gained access to portions of the company’s network and deployed ransomware,” Advantest states.

“If our investigation determines that customer or employee data was affected, we will notify impacted persons directly and provide guidance on protective measures.”

Currently, no data theft has been confirmed, but Advantest noted that this may change as more information emerges from the ongoing investigation.

Should customers or staff be determined to be impacted, Advantest will notify them directly and provide instructions on mitigating the associated risks.

At the time of writing, no ransomware groups have claimed the attack on the Japanese tech giant.

BleepingComputer has contacted Advantest directly to request more details about the attack, but we have not heard back by publishing time.

Multiple Japanese companies have been the target of cyberattacks recently, as several high-profile entities suffered data breaches and operational disruptions. Notable examples include Washington Hotel, Nissan, Muji, Asahi, and NTT.

Advantest says that the investigation continues and that it will provide updates on the incident when new details emerge.