The ransomware attack on UnitedHealth's Change Healthcare subsidiary last month not only brought to light how attractive the data-rich U.S. health-care industry is to hackers and how devastating the consequences for patients and doctors, but also how sophisticated cyber criminals are becoming when targeting vulnerable sectors. The breach, which took place more than three weeks ago, prompted the U.S. Department of Health and Human Services this week to launch an investigation into UnitedHealth. In a statemen ...