Duluth, Minn.-based Essentia Health mailed letters to 1,000 patients regarding a data breach at a third-party vendor that may have exposed their protected health information, according to CBS3.
One of the health system's vendors that helps with billing services, Nemadji Research Corp., was the target of a phishing attack. Essentia Health confirmed July 10 that no patient information has been misused.
The health system said the data breach affected patients at its hospitals in Minnesota, Wisconsin and North Dakota.
Essentia Health has since opened an investigation into the incident. Patients who were affected are being offered free credit monitoring services.