Kudankulam nuclear plant files leaked by ransomware group, contractor confirms breach
Nearly 19,000 files related to the Kudankulam nuclear power plant in Tamil Nadu, India's largest atomic facility, have been posted on the dark web by a ransomware group known as World Leaks. The files include purported blueprints of parts of the plant and supplier details, according to a cybersecurity researcher who alerted Reuters to the leak.
The contractor Reliance Group, owned by businessman Anil Ambani, confirmed a 'partial breach' of its data hosted on a server by third-party data centre provider Yotta. In a statement, Reliance said the government has been informed about the incident but did not disclose what data was breached.
The leaked data, which dates from 2016 to mid-2025, also appears to contain meeting and inspection records, equipment reviews and insurance policies. The authenticity of the documents could not be independently verified by Reuters.
The breach could pose 'serious' risks to the safety of the plant, according to Nickolas Roth, a senior director at the Nuclear Threat Initiative, which advises governments on nuclear security. The incident highlights the growing frequency of cyberattacks in India, where many companies remain vulnerable.
World Leaks, which had earlier targeted Nike and India’s Tata Group, typically posts stolen corporate data after companies refuse to pay ransom. In June, the group claimed it had demanded $1.5 million from Tata for similar data. The group did not respond to queries about this breach.
Yotta said it detected suspicious activity on May 29 on a server hosting Reliance Infrastructure data, and that the suspected ransomware execution was prevented. However, Reliance Infrastructure informed Yotta at the end of June about claims of a data breach by external threat actors. Yotta said it had shared its technical findings with Reliance and is supporting an ongoing investigation.
The Nuclear Power Corporation of India (NPCIL) has been in communication with Reliance about the breach, and India's cybersecurity agency CERT-In is investigating, according to a source familiar with the matter. NPCIL Chairman Rajesh Veeraraghavan and CERT-In did not respond to requests for comment.
The Kudankulam plant is central to Prime Minister Narendra Modi's plans to expand India's atomic energy capacity. Units 3 and 4, still under construction and due to be operational by 2027, are being built by Reliance Infrastructure under a contract awarded in 2018.
