DaVita, a major US-based kidney dialysis provider, has confirmed a significant data breach that compromised the personal and clinical data of over 900,000 customers. The incident, which began on March 24, 2025, and continued until April 12, involved an unauthorized actor gaining access to and removing sensitive information from the company’s dialysis labs database. The stolen data is extensive, including a wide range of personally identifiable information and clinical details, which poses a serious risk to the affected individuals. DaVita has since notified all 915,952 impacted US residents, urging them to be vigilant against potential identity theft and fraud.
The breadth of the stolen information is particularly concerning for the affected patients. According to a notification letter sent by DaVita, the compromised data includes names, dates of birth, Social Security numbers, and health insurance information. Furthermore, the breach exposed sensitive clinical data, such as health conditions, treatment details, and specific dialysis lab test results. In some cases, the attackers also accessed tax identification numbers and images of checks written to DaVita. The varied nature of the compromised information means that the potential for harm, from financial fraud to medical identity theft, differs significantly among individuals, underscoring the need for heightened vigilance.
The financial fallout from the cyber-attack has been substantial for DaVita. In its second-quarter 2025 financial results, the company revealed that the incident cost approximately $13.5 million to address. This figure includes expenses for remediation and system restoration, which were carried out with the assistance of third-party cybersecurity experts. The company noted that patient care costs increased by $1 million, while general and administrative expenses rose by $12.5 million as a direct result of the breach. This significant financial impact highlights the costly consequences of cybersecurity failures for healthcare providers and the broader implications for their operational budgets.
While DaVita has not officially confirmed the perpetrator, the Interlock ransomware group has claimed responsibility for the attack.
In April, the group added DaVita to its data leak site, alleging it had stolen 1.5 TB of data. To substantiate its claim, Interlock posted images purporting to be part of the stolen dataset. The group’s alleged involvement aligns with the timeline of the breach and the nature of the attack, which often involves both data exfiltration and subsequent ransom demands. This incident adds DaVita to a growing list of healthcare organizations targeted by ransomware gangs seeking to exploit sensitive patient data for financial gain.
In response to the breach, DaVita has taken steps to support the impacted customers. The company is offering free credit monitoring services to all those affected, a common measure taken by organizations following a major data breach. This service is intended to help individuals detect and mitigate potential fraudulent activities resulting from their compromised information. As the healthcare industry continues to be a prime target for cyberattacks, this incident serves as a stark reminder of the critical importance of robust cybersecurity measures to protect patient data and prevent both financial and reputational damage.
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