I knew about North Korean hackers—they still tricked me and got into my computer

In late March, I received a troubling message from Fortune’s IT administrator. “There is a process that’s exposing a vulnerability,” he wrote, telling me that someone may be prowling around my computer. “I need to kill it.” I panicked. A file I had downloaded at 11:04 a.m. had the capacity to monitor my keyboard strokes, record my computer screen, see my passwords, and access my apps, according to logs later reviewed by Fortune’s IT department.

After shutting down my laptop, I rushed...