Cookeville Regional Medical Center Discloses Rhysida Ransomware Attack Affecting 337,917 Patients
A major Rhysida ransomware breach has hit Cookeville Regional Medical Center (CRMC) in Tennessee, exposing the personal and medical data of 337,917 individuals. The hospital confirmed the incident this week, sending breach notification letters to affected patients nearly nine months after the attack was first detected.
This healthcare ransomware attack, which occurred in July 2025, ranks among the largest in the United States for that year. The 309-bed facility serves about 250,000 patients annually across 14 counties in the Upper Cumberland region, making the scale of the data compromise particularly concerning for the local community.
How the Rhysida Ransomware Breach Unfolded at CRMC
According to a filing with the Maine Attorney General’s Office, an unauthorized party accessed or acquired files between July 11 and July 14, 2025. The Rhysida ransomware group, a Russia-linked ransomware-as-a-service operation active since May 2023, claimed responsibility on August 2, 2025. The gang demanded a ransom of 10 Bitcoin—worth roughly $1.15 million at the time—and posted sample files on its dark web leak site. It remains unclear whether any ransom was paid.
The hospital began mailing notification letters on April 14, 2026, roughly nine months after the intrusion. This delay, while typical for complex investigations, left patients in a prolonged state of uncertainty about their data security.
Data Exposed in the Attack
The compromised information may include names, addresses, dates of birth, Social Security numbers, driver’s license numbers, financial account details, medical record numbers, treatment information, and health insurance data. CRMC is offering 12 months of free identity theft protection through Experian to those affected.
Given the sensitive nature of medical records, this Rhysida ransomware breach poses significant risks for identity theft and medical fraud. Patients are advised to monitor their accounts closely and take advantage of the offered protection services.
The Growing Threat of Rhysida Ransomware in Healthcare
The CRMC incident is not an isolated case. According to Comparitech, which tracks healthcare breaches, this ranks as the eighth-largest US healthcare ransomware breach of 2025 by records compromised. Last year, there were 134 confirmed attacks on US healthcare providers, exposing 11.7 million records in total.
Rhysida alone claimed 91 attacks across all sectors in 2025, with 23 confirmed. The average ransom demand from the group was $1.2 million. Other recent healthcare victims of Rhysida include Florida Lung, Asthma & Sleep Specialists (May 2025, $639,000 demand), MedStar Health in Maryland (September 2025, $3.09 million demand), and Spindletop Center in Texas (September 2025, $1.65 million demand).
These incidents highlight the persistent targeting of the healthcare sector by ransomware groups. For more on Rhysida’s tactics, see our analysis on Rhysida Ransomware Analysis Reveals Vice Society Connection.
Why Breach Notifications Take So Long
Rebecca Moody, head of data research at Comparitech, explained that the lengthy investigation timeline reflects the scale of forensic work required after a hospital ransomware hit. “It can take a considerable amount of time for organizations to investigate what data has been impacted in these breaches,” she said.
“While some organizations avoid using the word ‘ransomware’ and don’t issue any form of data breach notification for months,” Moody added, “this lack of clarity and confirmation can leave those affected open to identity theft and phishing campaigns.” CRMC, however, has been transparent about the nature of the attack, which helps patients understand the risks they face.
Impact on Patient Care and Hospital Operations
Ransomware incidents at US hospitals routinely force extended downtime, canceled appointments, and patient diversions, even when clinical systems remain operational. In CRMC’s case, the hospital stated it has put additional security measures in place since the attack to prevent future incidents.
For patients, the immediate concern is the potential misuse of their data. Social Security numbers and medical records are particularly valuable on the black market, often fetching higher prices than credit card numbers. This means that even if no direct financial loss occurs, victims may face long-term risks such as fraudulent medical claims or identity theft.
Healthcare organizations across the country are increasingly investing in cybersecurity defenses, but as the CRMC case shows, the threat from groups like Rhysida remains potent. For more insights on protecting patient data, read our guide on Healthcare Cybersecurity Best Practices.
In conclusion, the Rhysida ransomware breach at Cookeville Regional Medical Center underscores the urgent need for robust cybersecurity in healthcare. With 337,917 patients affected and sensitive data exposed, this incident serves as a stark reminder of the vulnerabilities in our medical infrastructure. Patients are urged to remain vigilant and take advantage of identity protection services offered by the hospital.
