Ransomware Disrupts McLaren and Ascension, With Ascension Breach Hitting 5.6 Million

McLaren Health Care confirmed it was hit by a ransomware attack that disrupted clinical and business operations across its Michigan network, forcing the organization to rely on downtime procedures and warning that recovery would extend into September. Follow-up reporting said McLaren was still restoring systems weeks later and had not yet determined whether patient or employee data had been accessed or stolen, leaving the scope of any data compromise unclear as the health system worked to bring affected services back online.

Ascension, one of the largest U.S. health systems, also suffered a major cyberattack that caused widespread outages, diverted ambulances, and disrupted electronic health records, phone systems, and other care operations; reporting at the time linked the incident to suspected Black Basta ransomware activity. Later disclosures said the attack resulted in a data breach affecting 5.6 million people, exposing personal, insurance, medical, and payment-related information and underscoring how ransomware incidents in healthcare can escalate from operational disruption to large-scale compromise of sensitive patient data.