Generations, of U.S. counterintelligence officers have sniffed out foreign agents by sifting through their personal lives. A fat bank account was a flashing red light, as were signs of newfound wealth (like the pricey Jaguar purchased by the infamous CIA mole Aldrich Ames with the aid of Soviet funds). Anything that made a U.S. employee in a sensitive post vulnerable to blackmail set off alarms--a drug habit, for example, or sexual practices that could lead to embarrassment if exposed.

But the days of relying on those signals could be over. According to a March Pentagon study titled Changes in Espionage by...

Want the full story?

Subscribe Now


Get TIME the way you want it

  • One Week Digital Pass — $4.99
  • Monthly Pay-As-You-Go DIGITAL ACCESS$2.99
  • One Year ALL ACCESSJust $30!   Best Deal!
    Print Magazine + Digital Edition + Subscriber-only Content on TIME.com

Learn more about the benefits of being a TIME subscriber

If you are already a subscriber sign up — registration is free!