Ransomware Group Claims Leak Of Files Linked To India's Largest Nuclear Plant, Kudankulam

A ransomware group has published a large cache of files allegedly linked to India's Kudankulam Nuclear Power Plant on the dark web, raising fresh concerns over cybersecurity at the country's largest nuclear facility.

Alleged data leak surfaces

According to a Reuters report, the group known as World Leaks uploaded around 19,000 files, purportedly sourced from Anil Ambani-led Reliance Group, one of the contractors involved in the Tamil Nadu-based nuclear project. Reuters reviewed the documents but said it could not independently verify their authenticity.

The leaked files, dated between 2016 and mid-2025, reportedly include blueprints of ventilation and cooling systems, supplier information, meeting records, equipment inspection reports and insurance documents related to Units 3 and 4, which are currently under construction.

Reliance, Yotta respond

Reliance Group told Reuters that it had experienced a "partial breach" involving data stored on a server hosted by third-party data centre provider Yotta. The conglomerate said it had informed the government but did not specify what information had been compromised.

Yotta stated it detected suspicious activity on a Reliance Infrastructure server in May, terminated the activity immediately and prevented the suspected ransomware execution. However, it later learned of claims by external threat actors alleging a data breach. The company said it has been unable to verify those claims and is assisting with the ongoing investigation.

Investigation underway

Reuters reported that the Nuclear Power Corporation of India has been coordinating with Reliance, while the Indian Computer Emergency Response Team (CERT-In) is examining the incident.

Cybersecurity experts warned that, if authentic, the leaked documents could help adversaries identify suppliers, map support systems and potentially expose vulnerabilities in the plant's security infrastructure. However, the documents do not appear to include information related to the nuclear reactors' core systems supplied by Russia's Rosatom.