Michael Dulak joined troops, civilians and leaders in the Pentagon courtyard for a 25th anniversary September 11 observance hosted by the Secretary of War. The group intended to pray, honor victims and first responders, and pair memory with alertness.

He said counterintelligence must never underrate how far opponents will stretch, adding that idea to James Olson’s ten principles in To Catch a Spy, among them staying offensive, knowing history and not quitting. Officials have missed threats because they cannot picture foes breaking usual patterns, as when Japanese consulate spies in Honolulu helped plan the 1941 Pearl Harbor attack.

Foreign services now seek defense data inside the United States via social media and messages to service members, Pentagon workers and contractors, using online targeting to obtain secrets and trigger leaks.