India's nuclear data at risk! over 19,000 sensitive files of largest plant leaked on dark web

The ransomware group World Leaks has published over 19,000 sensitive files related to India’s largest nuclear power plant, Kudankulam, on the dark web. The exposed data is part of a larger cache of approximately 858,000 files stolen from Reliance Group, a contractor for the facility. Reliance Group confirmed that a partial data breach occurred on a server hosted by third-party data center provider Yotta, and the government has been informed of the incident.

The leaked documents, dated from 2016 to mid-2025, contain engineering blueprints for ventilation and cooling systems, control room floor layouts, and equipment reports. These files primarily relate to Units 3 and 4 of the Kudankulam plant in Tamil Nadu, which are currently under construction. Although the leak does not appear to compromise the core reactor systems supplied by Russia's Rosatom, security experts warn that the exposed infrastructure and vendor data still pose a serious risk.

An investigation is currently underway by India's Computer Emergency Response Team (CERT-In) alongside the Nuclear Power Corporation of India (NPCIL). While Yotta reported preventing a suspected ransomware execution on May 29, Reliance Infrastructure later flagged claims of a breach. This incident highlights escalating cybersecurity concerns in India, where recent industry data shows a severe lack of cyber hygiene and awareness across critical infrastructure organizations.