Data breach at NTT impacts thousands of companies

This breach is part of a troubling trend for the Japanese telecom service provider, following a January 2025 DDoS attack that disrupted services for 12 hours, and a May 2020 hack that compromised sensitive data from the company's internal network

Japanese telecom giant NTT Communications Corporation has warned approximately 18,000 corporate clients of a data breach that may have compromised their sensitive information. The NTT Communications breach, discovered in early February 2025, is still under investigation, though the precise timing of when hackers first gained access to the company's systems remains unclear.

The company confirmed in an official announcement that unauthorized access was detected on February 5, 2025. By February 6, NTT stated that it had confirmed a possible external leak of data. The breach targeted NTT's "Order Information Distribution System," which contains critical details about its corporate customers, including customer names, contract numbers, contact information, and service usage. However, NTT emphasized that no consumer data was involved in the breach, and corporate smartphone contracts from NTT Docomo were not affected.

The compromised data may include sensitive information such as registered contract names, customer representatives' names, phone numbers, email addresses, physical addresses, and service usage records. Fortunately, no personal customer data was involved in the incident, limiting the scope of the breach to corporate accounts only.

NTT responds swiftly to security threat

NTT quickly responded to the incident, blocking access to the affected system by February 6. However, further investigation revealed on February 15 that the attackers had shifted to another device within NTT's network. The company promptly disconnected this device to prevent any further unauthorized movement within its systems. By mid-February, NTT assured the public that the threat had been fully contained, and no additional breaches were detected.

In its public statement, NTT confirmed it would not be sending individualized notifications to affected customers. Instead, the company opted to make a general public announcement on its website, urging impacted clients to stay informed through this channel.

This breach is the latest in a series of security incidents that have affected NTT. On January 2, 2025, the company faced a significant 12-hour service disruption due to a Distributed Denial of Service (DDoS) attack on its mobile services and payment platforms. Additionally, in May 2020, another NTT hack was reported, in which hackers gained access to sensitive data from its internal network.

As one of Japan’s largest telecom operators, NTT continues to be a high-value target for cybercriminals, with its expansive network and sensitive data making it an attractive asset for potential attacks. The company is now working closely with cybersecurity experts to strengthen its network security and prevent future incidents.

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