On April 20, the hospitals learned that malicious code had infected their networks as a result of an unauthorized party gaining access to certain systems between ??March 31 and April 24.

According to the Washington University School of Medicine's website, the health system learned that an unauthorized person gained access to certain employee email accounts between March 4 and March 28.

The hospital discovered hackers had breached its networks on the morning of November 11. It is working with law enforcement and cybersecurity firms to investigate the scope of the breach.

UMass Memorial Health began notifying 3,099 patients that hackers breached employee email accounts, according to data the organization shared with the Maine attorney general's office on October 15.

The patient information exposed by the incident included names, birthdates, Social Security numbers, treatment details, prescription details, and health insurance details.

The center didn't confirm if the attack was related to ransomware. Exposed information may include SSNs, names, addresses, birthdates, credit card numbers, and health-related information.