A government-mandated tracking system poses a threat to the military’s most advanced fighter jets if security flaws are left unaddressed.

According to a Government Accountability Office (GAO) report released earlier this month, steps to modernize the global air-traffic-control system could allow anyone to track U.S. stealth jets like the F-22 and F-35, and leaves military aircraft vulnerable to cyberattacks and electronic warfare.

The security risks stem from a Federal Aviation Administration (FAA) plan to move from ground-based radars to a satellite system that automatically reports an aircraft’s position, heading, and other critical information.

With commercial air traffic projected to double by 2030, air-traffic controllers around the world are adopting this satellite-based system, as it promises to reduce delays, increase safety, lower fuel consumption and allow for increased air traffic, besides being cheaper to operate than radars.

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As part of its modernization efforts, the FAA has issued a rule that requires all aircraft—military and civilian—operating within U.S. national airspace to be equipped with Automatic Dependent Surveillance-Broadcast (ADS-B) Out transponders, which broadcast its position via satellite, by January 1, 2020.

Under the previous radar-based system, aircraft were equipped with Mode S transponders, which only shared basic data like the aircraft’s altitude and unique transponder code. But ADS-B Out transponders convey significantly more information—and this is what poses a security threat.

ADS-B Out transponders broadcast sensitive data like a plane’s precise location, velocity and airframe dimensions, which anyone with an ADS-B In receiver can access. In the past, the FAA was able to filter out military flights, so this data was not publically accessible. However, ADS-B broadcasts information directly from the aircraft, where the FAA cannot filter it out. As a result, using publicly available data, GAO researchers were able to track various military aircraft.

By monitoring military planes over time as they enter and exit restricted airspace, the report warns that private citizens and adversaries can easily ascertain flight patterns and operational procedures. A 2015 RAND assessment found that broadcasting detailed and unencrypted position data for stealth jets—like the F-22—poses a security risk. Moreover, ADS-B-equipped aircraft could even compromise sensitive missions in U.S. airspace like counterterrorism, counter-drug and key personnel transport.

In addition to making sensitive military flight data publicly available, the report warns that ADS-B Out is susceptible to electronic warfare and cyberattacks.

According to the Institute of Electrical and Electronics Engineers, adversaries can exploit the ADS-B system using a jamming attack to hijack the transponder’s signal and wreak havoc with ground controllers. By transmitting a higher-power signal on ADS-B frequencies, adversaries could create enemy “ghost” aircraft on the ground or in the air, alter reported flight paths, or make friendly planes disappear entirely.

This vulnerability could also compromise future air-defense and air-traffic missions. The North American Aerospace Defense Command (NORAD) relies on information from the FAA to monitor air traffic, but as the FAA abandons its ground-based radar stations in favor of the ADS-B system, it is left exposed to a cyberattack.

The GAO urges the Department of Defense (DOD) and the FAA to immediately implement solutions to address these security concerns, and cautions that if they do not act swiftly, “they may not have time to plan and execute actions that may be needed before January 1, 2020—when all aircraft are required to be equipped with ADS-B Out technology.”

In 2008, the DOD and the FAA identified critical security risks in transitioning to the ADS-B system, but to date, the Pentagon has been primarily focused on meeting the deadline to equip all military aircraft with the technology rather than mitigating its risks.

DOD has more than fifteen thousand fixed- and rotary-wing aircraft across the Army, Air Force, Navy and Marine Corps, and installing ADS-B out transponders on each of these aircraft is expected to cost some $3 billion.

The report concludes, “unless DOD and FAA focus their efforts on the security aspects of ADS-B on DOD aircraft and produce one or more solutions to these risks, DOD aircraft and missions will be exposed to unmitigated risks that could jeopardize safety, security, and mission success.”

Eugene K. Chow writes on foreign policy and military affairs. His work has been published in Foreign Policy, The Week, and The Diplomat.

Image: A Lockheed Martin F-35 "Lightning II" flies around the airspace of Davis-Monthan Air Force Base, Ariz., March 5, 2016. The F-35 was participating in Air Combat Command’s Heritage Flight Training Course, a program that features modern fighter and attack aircraft flying alongside Word War II, Korean War and Vietnam War-era aircraft.​ Flickr / Robert Sullivan