After years of being caught flat-footed by hackers, companies are turning to cybersecurity defenses called threat intelligence to fend off a new generation of criminals and spies trying to steal their secrets and money.

Threat-intelligence services can include detailed reports on the makeup and motivations of illicit groups, descriptions of illegal data sold on the dark web, and information about hackers’ tools and tricks. Incubated in the military and in spy agencies, they are becoming more popular in an era when companies...