UW Medicine has started notifying about 90,000 of its patients that medical information was stolen during a malware attack last month, including 15,000 cases in which Social Security numbers may have been taken.
The attack happened when a UW Medicine employee opened an email attachment that contained malicious software, or malware, on Oct. 2.
UW Medicine — which includes UW Medical Center and Harborview Medical Center — discovered the attack Oct. 3 and shut it down, said UW Medicine spokeswoman Tina Mankowski.
It took more than a month to analyze the activity and figure out which patients are most at risk of identity theft, she said. The UW believes that the people behind the malware were not seeking or targeting medical information.