McLaren Health Care Hit by Major Data Breach Affecting Over 743,000 Individuals
McLaren Health Care, a major healthcare provider in Michigan, has confirmed another large-scale data breach that compromised the personally identifiable information (PII) and protected health information (PHI) of 743,000 individuals.
The organization disclosed the incident through a breach notification filed with the Office of the Maine Attorney General, revealing that it had detected “suspicious activity” involving its systems and those of Karmanos Cancer Institute—part of the McLaren network—during August 2024.
Hackers Accessed the Network Over a Two-Week Period
The internal investigation, conducted with third-party forensic experts, determined that unauthorized access occurred between July 17 and August 3, 2024. During this period, attackers infiltrated McLaren’s network and accessed files containing sensitive personal and health data.
The exposed information includes:
- Full names
- Social Security numbers
- Driver’s license numbers
- Medical information
- Health insurance details
The compromised data could allow threat actors to engage in medical identity theft, a fraud technique where stolen medical information is used to submit false insurance claims. Meanwhile, PII such as Social Security and license numbers can enable more traditional forms of identity fraud, including phishing and account takeovers.
History of Ransomware Attacks Raises Additional Concern
McLaren did not confirm whether the latest breach was ransomware-related. However, the organization has previously suffered a significant ransomware attack in 2023.
In that prior incident, attackers infiltrated McLaren’s systems and remained undetected for nearly a month. By September 2023, the ALPHV ransomware gang (BlackCat) publicly claimed responsibility by listing McLaren on its dark web blog. At the time, the stolen data set included:
- Names
- Social Security numbers
- Health insurance data
- Dates of birth
- Claims and diagnosis details
- Medical record numbers
The 2023 attack reportedly impacted more than 2 million individuals, drawing scrutiny to the organization’s cybersecurity posture.
McLaren Health Care’s Size and Scope
McLaren Health Care operates 3,100 licensed beds and provides care to over 732,000 members through its health maintenance organization (HMO) plans. As of 2024, the organization reported a net revenue of $6.6 billion, making it one of the region’s most substantial healthcare networks.
The Growing Risk of Healthcare Cyberattacks
Healthcare providers continue to face mounting cyber threats, driven by the high black-market value of patient data. Medical records, in particular, can fetch hundreds of dollars on the dark web, making hospitals and health systems prime targets for cybercriminals.
Looking for a trusted recovery solution?
Defend your organization with StoneFly DR365—an air-gapped, immutable backup and recovery appliance trusted by enterprises to ensure zero data loss even in the event of complex cyberattacks.
