The Federal Aviation Administration has dismissed a Spanish security researcher's claims that an airplane flight management system used by pilots could be taken over by an Android app running on a local mobile device and used to seize control of an airplane's navigation systems or autopilot.
The warning of exploitable vulnerabilities in flight management system software was sounded Wednesday by Spanish security researcher Hugo Teso, who works for consultancy N.Runs in Germany. Teso, an avid pilot who's also certified to fly commercial aircraft, demonstrated how a "PlaneSploit" Android app he built, together with an antenna, could be used to locally spoof ACARS (Aircraft Communications Addressing and Reporting System) data received by FMS software, and adjust the heading, altitude and speed of an airplane.
But Teso's presentation carried a caveat: the vulnerabilities he exploited existed in PC-based ACARS training software. Purposefully, Teso chose to not test his exploits against systems in actual airplanes.
[ For more on the purported Android-based takedown hack, see Airplane Takeover Demonstrated Via Android App. ]
The good news, according to the FAA, is that systems certified for use on flight decks are immune to the exploits detailed by Teso. "The FAA is aware that a German information technology consultant has alleged he has detected a security issue with the Honeywell NZ-2000 Flight Management System (FMS) using only a desktop computer," read a statement released Thursday by the agency. "The FAA has determined that the hacking technique described during a recent computer security conference does not pose a flight safety concern because it does not work on certified flight hardware."
Teso had suggested that feeding incorrect information to ACARS would lead to the plane's autopilot applying that information to alter heading, pitch or altitude. But the FAA said that's not possible. "The described technique cannot engage or control the aircraft's autopilot system using the FMS or prevent a pilot from overriding the autopilot," the FAA's statement said. "Therefore, a hacker cannot obtain 'full control of an aircraft' as the technology consultant has claimed."
The FAA's statement squares with information released Thursday by the European Aviation Safety Administration (EASA), which noted that "this presentation was based on a PC training simulator and did not reveal potential vulnerabilities on actual flying systems."
"There are major differences between a PC-based training FMS software and an embedded FMS software," said EASA. "In particular, the FMS simulation software does not have the same overwriting protection and redundancies that is included in the certified flight software."
Contacted for comment on Teso's research, two of the potentially affected manufacturers voiced a similar perspective. "Today's certified avionics systems are designed and built with high levels of redundancy and security," said Rockwell Collins spokeswoman Pam Tvrdy-Cleary via email. "The research by Hugo Teso involves testing with virtual aircraft in a lab environment, which is not analogous to certified aircraft and systems operating in regulated airspace."
Likewise, Honeywell spokesman Scott Sayres emphasized that the company's certified FMS has security and safety safeguards designed to prevent data corruption and data overwriting.
What's not clear to date, however, is whether the attack won't work on certified flight management systems because it's running software that's completely different to what Teso tested, or because of the overwriting protection, redundancies and other security and safety controls built into certified systems. The worry with the latter scenario is that the exploits that have been identified to date could be used as stepping stones to discovering new types of exploits.
N.Runs first detailed the FMS training software vulnerabilities it discovered to the European Aviation Safety Administration (EASA) several weeks ago, which distributed the information to the FAA as well as to affected manufacturers, who were named as being Honeywell, Rockwell Collins and Thales. (Thales didn't respond to a request for comment on Teso's research.) Teso said he procured the FMS hardware and software he tested over the past three years largely via eBay.
Teso wasn't immediately available to respond to the FAA and EASA statements. But Teso's supervisor at N.Runs, security researcher Roland Ehlies, suggested that the consultancy is trying to ensure that the vulnerabilities identified in the FMS software don't pose a threat.
"Aviation agencies and aircraft system manufacturers have even deeper knowledge about the inner workings of the affected systems," Ehlies said via email. "Our goal is to share the knowledge with the above-mentioned parties so that we can work together to understand the real implications of our findings and try to fix them and to prevent that additional security issues arise on aviation relayed technologies."
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