McLaren Health Care ransomware disrupts care, data of 743,000 leaked
In August 2024, McLaren Health Care suffered outages of its IT and phone systems and some patient services due to a ransomware attack. Radiotherapy and stroke care resumed, and systems and operations were restored later that month. In June 2025, the company notified about 743,000 patients of the data breach.
Key facts
- Affected organisation
- McLaren Health Care
- Incident type
- Ransomware
- Occurred / detected
- Not confirmed
- Scale of damage
- Data of about 743,000 patients leaked; disruption of care and systems
- Cause / method
- Ransomware attack
- Location
- United States
Timeline
- McLaren Health Care confirmed that a cyber-attack had caused outages of its IT and phone systems.
- Radiotherapy and stroke care resumed at McLaren and Karmanos facilities.
- The incident was reported to be a ransomware attack.
- McLaren Health Care announced that operations had returned to normal.
- It was reported that the network shut down by the ransomware attack had been restored.
- McLaren Health Care notified about 743,000 patients of the data breach.
16 related reports
- Michigan’s McLaren Health Care confirms cyberattack, asks for ‘patience’
- McLaren Health Care confirms criminal cyberattack caused disruptions to IT, phone systems
- McLaren Health Care reports cyberattack affecting some patient services
- McLaren Health responds to second cyberattack in less than a year
- Radiation treatments, stroke care resume at McLaren and Karmanos sites after cyberattack
- McLaren Health Care hit by ransomware attack again
- McLaren Health Care: Operations back to normal after cyberattack
- McLaren Health Care systems restored after weeks of disruption from ransomware attack
- McLaren Health Care restores network weeks after ransomware attack
- McLaren operations restored after August cyberattack
- McLaren Health Care Notifies Almost 750,000 Individuals About August 2024 Ransomware Attack
- McLaren Health Care Data Breach Lawsuit Investigation
- McLaren Health Care says data breach impacts 743,000 patients
- McLaren notifies 743K patients about data breach
- Mclaren Health Care Data Breach Impacts Over 743,000 Patients
- 743,000 McLaren Patients Notified After Cyberattack
Other incidents at McLaren Health Care
Michigan's McLaren Health Care restores operations after cyber-attack
McLaren Health Care in Michigan was hit by a cyber-attack. It was reported on 15 May 2025 that operations had returned to normal, and the date of the attack and the extent of the damage have not been confirmed.
Related reports: 2 · last report →McLaren Health Care ransomware disrupts care, affects 740,000 people
740kImpact: 740,000 people affected; disruption of cancer treatment, cardiac testing and prescriptions
McLaren Health Care was hit by a ransomware attack in August 2024, disrupting cancer treatment, cardiac testing and prescriptions. The company's chief executive said cyber security experts were investigating the attack. About 10 months later, the company disclosed that 740,000 people had been affected.
Related reports: 4 · last report →McLaren Health Care ransomware attack leaks data of 2.2 million
2.2mImpact: Personal and sensitive medical information of about 2.2 million people
A breach that occurred in July–August 2023 at US hospital operator McLaren Health Care exposed the personal information of about 2.2 million people. The leaked information included names, Social Security numbers and sensitive medical information such as diagnoses, prescriptions and test results. McLaren Health Care sent breach notifications in November, and it also emerged that patient information had been stolen during a ransomware attack.
Related reports: 5 · last report →
The summary and key facts are written by AI from related reports and may contain errors. Check the original articles and the organisation’s official statements for accurate details.