"Our biggest challenge with the red teams is keeping the people", Shanahan said. "They are so talented and there is such high demand that we get out-recruited, so anything we can do to generate capacity is extremely critical".
About a dozen Department of Defence red teams parachute into different installations throughout the country and conduct these attacks so we can assess vulnerabilities, Shanahan said.
The US defence chief added that installations augment red team efforts by identifying and targeting the most critical risks.
The United States ranked fifth out of 60 nations listed in its effective cyber security, according to the Global Cyber Security Index published in February.