While defending security controls put in place after the Edward Snowden affair, the top U.S. counterintelligence official says secret government data remains vulnerable to determined thieves.

Bill Evanina told The Associated Press in a recent interview that he believes reforms are working. But he says that if someone wakes up one morning and decides to steal classified government data, they probably will get away with it.

His remarks were the most extensive comments he’s made since former National Security Agency contractor Harold Martin III of Glen Burnie, Maryland, was arrested and accused of working undetected for 20 years to steal a trove of classified material.

Evanina says that even the best security controls won’t catch every insider or hacker — and they must be updated with technological advances.

(AP)