BENGALURU: A leak from the Kudankulam nuclear plant exposed nearly 19,000 files after a ransomware group, World Leaks, posted contractor data on the dark web, according to reports.
Reliance Infrastructure Limited confirmed a partial breach involving its data on a server hosted by Yotta Data Services. The company said it had informed the Indian government.
Cybersecurity researcher Rakesh Krishnan identified 14.3 gigabytes of files linked to the plant. The documents had remained online since June 11, according to records dated from 2016 to mid-2025. It could not verify their authenticity.
The files appeared to include blueprints, supplier details and inspection records. Some documents showed ventilation, cooling and common control-room layouts for Units 3 and 4.
The Nuclear Power Corporation of India Limited said the material covered common service facilities. It said the information did not involve nuclear safety or security systems.
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Russia’s state-owned Rosatom supplies the reactors’ core systems. The leaked documents did not appear to cover those systems.
Yotta said it detected suspicious server activity on May 29 and stopped it. The company said it could not confirm the threat group’s breach claims.
The Indian Computer Emergency Response Team is examining the incident. Nickolas Roth of the Nuclear Threat Initiative said hostile actors could use such files to map support systems and identify suppliers.
