A Department of Homeland Security official admitted that the agency was able to remotely hack into a Boeing 757 during a test in 2016.

The DHS official indicated that he and his team were able to do so without having any direct contact with the aircraft or using any materials that would be flagged by security.

While the exact details of the hack are confidential, Boeing insists that the hackers were not able to take control of the aircraft’s flight systems.

The increasing use of electronics and internet connectivity in transportation vehicles is a double-edged sword. While new technology gives drivers and pilots more information and makes communication easier, it also leaves vehicles more vulnerable to cyber attacks.

The Department of Homeland Security illustrated that fact when it remotely hacked into a Boeing 757 through its radio communication system at an airport in Atlantic City, NJ, according to CSO. While the hack occurred in September 2016, it wasn’t revealed until DHS official Robert Hickey gave his keynote address at an aerospace security summit on Nov. 8.

Though the exact details of how he and his team managed to hack into the plane are classified, Hickey indicated that no one on his team was in physical contact with the aircraft or used any materials that would be flagged by security. Boeing insists that the hack was limited to the aircraft’s communication system and did not reach any of the controls or software that could alter its flight path.

“We witnessed the test and can say unequivocally that there was no hack of the airplane’s flight control systems,” the company told the Daily Beast.

Still, this is alarming news for the aviation industry. The Department of Homeland Security and Transportation Security Administration have been aggressive in trying to prevent passengers from boarding aircraft with items that could put other passengers at risk, but if it becomes possible to control a plane’s communication and flight capabilities from the ground, their existing security infrastructure may need a significant update.