The warning was the conclusion of a 56-page report published by the Government Accounting Office (GAO) into how the Federal Aviation Administration (FAA) is addressing cyberthreats as it deals with modernization of the national air traffic control system and increasingly connected aircraft.
While the FAA has taken steps to protect against cyberattacks, the GAO found "significant security-control weaknesses remain that threaten the agency's ability to ensure the safe and uninterrupted operation of the national airspace system."
The FAA has agreed to address the specific weaknesses identified in the report, but the GAO said the air traffic control system remains vulnerable because the FAA hasn't conducted an overall study that would identify potential threats to information systems and bring order to its current cyberthreat management, which is shared between several FAA offices.
"While FAA has taken some steps toward developing such a model, it has no plans to produce one and has not assessed the funding or time that would be needed to do so," the GAO said. "Without such a model, FAA may not be allocating resources properly to guard against the most significant cybersecurity threats."
The GAO, which audits and evaluates government agencies and departments, is clashing with the FAA on the degree to which the agency's office of safety should be involved in overall cyberthreat planning.
One of the jobs of the FAA's safety office is to certify interconnected networks on aircraft, such as the avionics system and in-flight Internet system, to ensure the aircraft isn't vulnerable to hackers. The GAO has recommended the FAA make the safety office a member of its Cyber Security Steering Committee, but the FAA has resisted the call, it said.
"Not including [the office of safety] as a full member could hinder FAA's efforts to develop a coordinated, holistic, agency-wide approach to cybersecurity," the GAO said.
The report comes as the FAA is working on development and deployment of the Next Generation Air Transportation System, a new air traffic control system that is intended to let more planes fly at once while making flying safer and more economical.
One component of the system, called the Surveillance and Broadcast Services Subsystem, is already in use. But the FAA has not adopted a 2013 government standard on security controls, such as intrusion detection improvements.
"Systems with weaknesses that could be exploited by adversaries may be at increased risk if relevant controls are not implemented," the GAO said.
The FAA could not immediately be reached for comment.
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is martyn_williams@idg.com