The Nucor Cyberattack: How Ransomware Threatens American Steel

Daily Security Review

In May 2025, a ransomware attack forced Nucor — one of America’s largest steel producers — to halt its metal production operations. This wasn’t just a corporate IT incident: it disrupted a critical link in the nation’s industrial supply chain.

In this episode, we take an in-depth look at the Nucor attack: how cybercriminals targeted operational technology (OT) systems, why manufacturers like Nucor are becoming prime ransomware targets, and what this means for national security.

We analyze the escalating tactics of ransomware groups, including sophisticated loader chains, abuse of legitimate tools, and emerging delivery methods that can take down even hardened industrial environments. We also examine why the attack on Nucor marks a new chapter in the ransomware threat landscape — one where physical production and critical infrastructure are increasingly at risk.

Most importantly, we discuss how organizations can defend against these evolving threats: leveraging the NIST Cybersecurity Framework, adopting proactive detection and incident response strategies, and addressing growing vulnerabilities in the cyber supply chain.

If Nucor’s shutdown taught us anything, it’s that no manufacturer can afford to ignore the ransomware threat. Tune in to learn what your organization can do to prepare.