Originally Posted by
Ian W
The computer that is running the ACARS software is _also_ the one in which a whole pile of other things run including the FMC, display processing, MCDU etc etc. So if he can make it run some exploit code by sending it a broken message that then allows him to upload some more code running at high authority, he has broken into the computer that is running around "80 - 100" of the major control applications of the aircraft.
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Uh... no. I am an avionics maintenance engineer of almost 40 years experience and I can assure you that the scenario you describe above is absolutely NOT how the integrated avionics system on a modern aircraft is implemented. There is no "common core" computer on which all of these various functions run. Each of the various sub systems that make up the complete avionics suite run on stand-alone, purpose-built discrete "black boxes". Until the last decade or so, the individual components of a complete aircraft avionics system literally were contained in rack-mounted boxes. In more modern systems, like the Rockwell-Collins Proline 21, the "boxes" have been replaced by plug-in circuit boards with edge-mount connectors, but the overall design of having functionality performed by discrete and specialized sub-systems remains the same.
ACARS is processed by a purpose-built, stand-alone AFIS computer. That is all it does. It is made to do one thing, and one thing only.
The FMS functionality resides on a purpose-built, stand-alone discrete navigation computer. It may do many things, but all of its funtionality resides within that computer, and though it may communicate with other onboard systems through a variety of data bus protocols, its internal workings are effectively walled off from other devices and systems in the aircraft.
Likewise the displays are driven by symbol generators. These again, are purpose-built, stand-alone, discrete units which are designed to do one specific thing - generate the grapics which appear on the cockpit displays.
The same holds true for the Flight Guidance Computer, the Performance Computer etc etc.
The "hacking" presentation made by Mr. Teso is based on PC-based emulations of various aircraft systems used for flight crew training, and though those emulations may exactly duplicate the look, feel and funtionality of the actual aircraft systems, their internal workings are COMPLETELY different.
The actual "black boxes" in a real aircraft contain embedded CPUs, data processors and software running on highly proprietary real-time operating systems which bear no realtionship in ANY way to the OS functions on a PC. For a hacker to use buffer overruns or the like to seize control of the processes of one of these units would require knowlege of the internal architecture of the hardware and software in the "black box" that no hacker (no matter how talented) could possibly have. If such knowlege IS "out there" in the hacker community, it would mean that manufacturers like Honeywell, Rockwell-Collins, Thales, L3 et al have all been victims of industrial espionage on a massive scale - which I very much doubt. Having worked closely with all of these manufacturers over the last 3+ decades, I can say that they all guard their trade secrets with bulldog tenacity.
That said, I certainly agree that open protocols like ACARS, ADS-B and the like are undoubtedly vulnerable. One scenario that comes to mind would be if a hacker gained access to an airline dispatch communications system - he could then cause a falsified flight plan routing to be uplinked to an aircraft when its crew requested the FP through ACARS. That could certainly have serious real-world consequences.... likewise if an ACARS exploit allowed a hacker to uplink completey false aircraft load manifest data to a crew before departure, and crew made takeoff performance calculations using that false data, again, the outcome could be very serious.
But these scenarios mainly highlight vulnerabilities in the external data support infrastructure of the airline industry... not glaring security holes within the various components that make up an aircraft's onboard avionics suite. While Mr. Teso's presentation makes some valid points, most of his claims regarding the supposed ease with which a hacker could seize control of an aircraft's systems with a smartphone are a complete load of codswallop.