Cyber Incident Victim: Lake County Health Department
Timeline
Summary
The Lake County Health Department notified patients of a data breach that resulted from a printing error causing some billing statements to contain incorrect patient information. Officials stated that no financial account information or Social Security numbers were involved and that there was no evidence of misuse. The agency noted that, in a prior incident, an unauthorized third party had accessed an employee's email account, potentially exposing names, addresses, dates of birth, medications, phone numbers, email addresses, diagnoses, and driver’s license numbers. Under Illinois law, the department was required to report the breach to the state attorney general and affected individuals.
| CIA Posture | Motives | Tactics, Techniques & Procedures |
|---|---|---|
| Available to members | 1 motive | 0 techniques |
| Threat Actors | Type | Location |
|---|---|---|
| 0 actors | Available to members | Available to members |
Description
Earlier in 2026 the Lake County Health Department identified a data breach that had occurred in May when a printing error caused some patient billing statements to contain incorrect information. The agency discovered the mistake during a routine review of outgoing mail and determined that the statements had been misprinted with data belonging to other individuals. Upon confirmation, the Health Department prepared and distributed breach notification letters to the affected patients as required by Illinois state law. In the notifications officials explained that the incident stemmed solely from the printing error and did not involve any unauthorized electronic access or hacking. They emphasized that no financial account information, Social Security Administration numbers, or health insurance identifiers were included in the misprinted statements. The agency also stated that there was no evidence that any of the disclosed information had been misused or accessed by unauthorized parties following the error.
The breach exposed personal details such as names, addresses, and possibly limited medical billing information, but the Health Department clarified that sensitive identifiers remained secure. Recipients of the notices were advised to review their statements for inaccuracies and to contact the department if they identified any discrepancies. The Health Department’s public statement noted that the incident was isolated to the printing process and that corrective measures had been implemented to prevent similar errors in future mailings. Officials also referenced the department’s prior experience with a September 2024 email account compromise, noting that the earlier incident had involved potential exposure of names, addresses, dates of birth, medications, phone numbers, email addresses, diagnoses, and driver’s license numbers, though no unauthorized data transfer was found at that time. They reiterated that, unlike the 2024 event, the May 2026 breach did not involve any electronic intrusion or phishing activity. The notifications concluded with an assurance that the Health Department remained committed to safeguarding patient information and would continue to monitor its processes for any further issues.