Today, most people have a passing understanding of what a bad guy with an internet connection can do. But you might be surprised how much of this kind of activity happens without direct human supervision. “Malicious computer programs that could be described as ‘intelligent autonomous agents’ are what steal people’s data, build bot-nets, lock people out of their systems until they pay ransom, and do most of the other work of cyber criminals,” says Scott Borg, director and chief economist of the U.S. Cyber Consequences Unit, a nonprofit research institute.

The damage done by such programs is not restricted to credit card stealing—cyber attacks also have the potential to inflict fairly widespread damage to physical infrastructure...