Ransomware or critical infra hit? Top US manufacturer maintains steely silence

Nucor, the largest steel manufacturer in the US, shut down production operations after discovering its servers had been penetrated.

In a Tuesday 8-K filing to America's Securities and Exchange Commission, the metals magnate said some of its facilities had been shut down while an unnamed third-party security company investigates an attack against "certain information technology systems," without specifying which ones. Law enforcement has also been called in to help.

"As of the date of this filing and in an abundance of caution, the company temporarily and proactively halted certain production operations at various locations. However, the company is currently in the process of restarting the affected operations," it wrote in its filing.

The steel shifter acknowledged the cyber-intrusion to The Register, but declined to say which facilities were affected and did not comment on the nature of the attack.

We called Nucor production facilities in Alabama, South Carolina, and ...