Massive Data Breach Exposes Sensitive Files from India’s Kudankulam Nuclear Power Plant India’s largest nuclear power facility, the Kudankulam Nuclear Power Plant (KKNP), has been hit by a significant data breach, with nearly 19,000 internal files leaked by the ransomware group World Leaks. The compromised data totaling 14.3 gigabytes includes highly sensitive documents such as engineering blueprints, supplier details, employee records, meeting logs, inspection reports, and insurance policies. The files, spanning from 2016 to mid-2025, first surfaced on the dark web on June 11 and remain accessible via searches for the plant’s abbreviation, "KKNP." The breach traces back to Reliance Infrastructure Limited, a subsidiary of India’s Reliance Group, which secured a 2018 contract to develop infrastructure for KKNP’s Units 3 and 4. These units, with a combined capacity of 2,000 megawatts, are still under construction and slated for completion by 2027. Reliance Group acknowledged the incident, confirming that data stored with a third-party Indian data center was "partially compromised" and that the Indian government had been notified. The Indian Computer Emergency Response Team (CERT-In) has since launched an investigation. World Leaks, known for targeting high-profile entities like Nike and India’s Tata Group, follows a standard ransomware playbook: exfiltrating data, encrypting systems, and leaking stolen files if ransom demands go unmet. While the 19,000 KKNP-related files represent only a fraction of the 850,000 files stolen from Reliance Infrastructure, they are considered the most critical subset. The breach has raised alarms among global security experts, with the U.S.-based Nuclear Threat Initiative warning that the leak could jeopardize the plant’s physical security. The incident underscores growing concerns over cyber threats to critical infrastructure, particularly in the nuclear sector.