Nucor, a leading steel manufacturer, admits to a cyber intrusion on its information technology system.
In a significant development, Nucor Corporation, the largest and most diversified steel and steel-products company in North America, has largely contained a cyberattack that occurred at its Charlotte, North Carolina-based facilities. The company, which produces approximately 25% of all raw steel in the U.S., temporarily halted production at various locations as a precautionary measure on May 2025.
Nucor Corp. has been working closely with external cybersecurity specialists to investigate the incident and has notified federal law enforcement regarding the cyberattack. The company proactively took potentially affected systems offline to prevent further damage.
While the exact nature of the data compromised during the cyberattack remains unknown, Nucor disclosed in a June 2025 SEC filing that attackers successfully exfiltrated limited data from its IT systems. The specific types of data and the number of individuals affected have not been detailed publicly.
Despite the data breach, the company indicated it does not anticipate a material impact on financial performance or business operations due to the incident. Nucor expects earnings growth across all operating segments, with a notable rise in its steel mills division.
Nucor has worked with external forensic experts and federal law enforcement for investigation and has reinforced its IT systems to prevent future attacks. The company is reviewing the breached data to notify any affected parties and regulators as required.
Although experts suspect a ransomware attack, no hacking group has publicly taken credit for the incident as of the latest updates. The company has not specified which operations will be restarted first or provided a timeline for when full production will resume.
In summary, Nucor has largely contained the cyberattack, resumed normal operations, and confirmed a data breach involving limited stolen data while continuing investigations and strengthening cybersecurity measures. The company continues to work diligently to restore affected operations and maintain its position as a leading steel producer in North America.
The cybersecurity industry and Nucor Corp. are collaborating to strengthen the company's IT systems and prevent future attacks, following the cyberattack on Nucor's Charlotte, North Carolina-based facilities that targeted both its finance and technology sectors. Despite the data breach, Nucor expects growth in its financial performance and steel mills division, demonstrating the resilience of the company in the face of this significant cybersecurity incident.
