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I agree with this basic sentiment, there is a whole class of problems that were "hard" before modern technology made them "easy". It is definitely interesting t

I agree with this basic sentiment, there is a whole class of problems that were "hard" before modern technology made them "easy". It is definitely interesting to look at legacy systems that relied on the 'difficulty' factor as part of their design as a protection against abuse. For example it was both inspiring and utterly brilliant in the way that Alan Turing broke the Enigma cipher with his Bombe machine, but today anyone who knew how Enigma worked (which England did at the time) with a modern laptop could exhaustively search the keyspace and 'crack' messages in real time. Software radios have made it possible for curious people to have "read/write" access to the entire spectrum between half a megahertz and six gigahertz. That will continue to be a problem for people who designed systems that depended on how "difficult" it was to build a radio at their particular frequency. That isn't the case for Aircraft navigation. Anyone who can pass the Amateur "General' class exam in the US has the necessary knowledge for interfering, potentially destructively, with aircraft navigation. I normally would consider that a non-issue except that Asian Airlines flew a plane into the runway at SFO. Is that a system problem? Or one where the pilot should be better trained? Arguments can probably made along those lines. But that interfering with navigation is possible with pretty much "off the shelf" components? Not really a new thing and certainly not something that is an imminent threat to passenger safety.

wolf550e 8y ago
I don't know how aircraft systems work. Can a directional antenna spoofing ILS [2] cause the crash of an airliner using ILS to land in bad visibility conditions? Does the plane trust the ILS signal? What if you combine that with a GPS jammer or GPS spoofer? Or do we consider that military technology, like MANPADs, and so out of scope? But some airlines consider MANPADs in scope, and use flares or laser systems to defend against them [1]. 1 - https://en.wikipedia.org/wiki/Flight_Guard https://en.wikipedia.org/wiki/Flight_Guard 2 - https://en.wikipedia.org/wiki/Instrument_landing_system https://en.wikipedia.org/wiki/Instrument_landing_system
- colechristensen 8y ago
  When you know answers to questions like this it becomes an ethical question whether to share your knowledge.
  - temac 8y ago
    It depends. We now have this little thing called the Internet, and you can quickly learn a ton of things on it. Even if you just learn a few points and without all the details, that's still better than nothing and at least a starting point for further study, if needed. And it depends on the direction of the answers too. For example I think most autoland still require some amount of visibility a few seconds before touchdown, and the pilots are supposed to go around if they do not have it. Plus, I believe planes also use a radio altimeter while landing. But I don't believe they use GPS for the final approach. So you might put a plane in a difficult position with that kind of attack, but not necessarily making it crash. And there are probably more easy ways to do more damage.
- throw20102010 8y ago
  Possibly, but the pilots would have to screw up as well. You typically tune in the ILS when you're expecting to pick up the approach. It's not like you set the ILS frequency hours before landing and just follow the first signal that pops up. So if you do follow a malicious signal, it's going to be few miles away from the airport at the furthest. However, ILS is becoming less used because it requires maintenance of ground systems. GPS approaches could also be spoofed, but would be a more sophisticated attack. But with GPS navigation you aren't tuning radio frequencies in your nav equipment so there's probably more chances to fool a pilot (you could drag them much further away from the airport if you started spoofing GPS further out). However, ALL instrument approaches have minimum visual altitudes, and the lowest I'm aware of is 200 ft above the ground. If you can't see the airport by the time you get down to the minimum altitude you execute a missed approach procedure- basically you climb and navigate to another waypoint to restart the approach or to hold. Additionally, all aircraft must have barometric altimeters as required equipment- no amount of radio spoofing can fool them. So in an ideal world an attack would go like this: the pilot follows the malicious approach, notices that they are at the minimum altitude, looks for the airport but doesn't see it (or sees it a few miles away), then executes a missed approach- no crash. There aren't too many tight approaches that could make you crash by being off by a mile. To get around this you would need to spoof either the pitot-static (pressure sensing) system, or the pilot's altimeter setting. You could only spoof the pitot-static system by sabatoge on the ground, and you can only realistically spoof the altimeter setting by pretending to be ATC on the radio- at which point the real ATC would correct whatever you said and get real suspicious. Of course, given that instrument landings are the highest workload portion of a flight, pilots get distracted. Even if they would normally catch on to the fact that they aren't on the correct approach, you might cause a few crashes by pilots that aren't on top of their game. Edit to add one more thing: Your plane is tracked by airborne surveillance as well, and if you claim to be at a waypoint and that doesn't match what ATC has on their scope they will warn you. So you'd have to also spoof a surveillance signal at the correct location while blocking the real planes signal to keep ATC from noticing.
  - tgsovlerkhgsel 8y ago
    > However, ALL instrument approaches have minimum visual altitudes, and the lowest I'm aware of is 200 ft above the ground. https://en.wikipedia.org/wiki/Instrument_landing_system#ILS_categories https://en.wikipedia.org/wiki/Instrument_landing_system#ILS_... claims "<50 ft" decision height for CAT IIIb.

wolf550e 8y ago

I don't know how aircraft systems work. Can a directional antenna spoofing ILS [2] cause the crash of an airliner using ILS to land in bad visibility conditions? Does the plane trust the ILS signal? What if you combine that with a GPS jammer or GPS spoofer? Or do we consider that military technology, like MANPADs, and so out of scope? But some airlines consider MANPADs in scope, and use flares or laser systems to defend against them [1]. 1 - https://en.wikipedia.org/wiki/Flight_Guard https://en.wikipedia.org/wiki/Flight_Guard 2 - https://en.wikipedia.org/wiki/Instrument_landing_system https://en.wikipedia.org/wiki/Instrument_landing_system

colechristensen 8y ago
When you know answers to questions like this it becomes an ethical question whether to share your knowledge.
- temac 8y ago
  It depends. We now have this little thing called the Internet, and you can quickly learn a ton of things on it. Even if you just learn a few points and without all the details, that's still better than nothing and at least a starting point for further study, if needed. And it depends on the direction of the answers too. For example I think most autoland still require some amount of visibility a few seconds before touchdown, and the pilots are supposed to go around if they do not have it. Plus, I believe planes also use a radio altimeter while landing. But I don't believe they use GPS for the final approach. So you might put a plane in a difficult position with that kind of attack, but not necessarily making it crash. And there are probably more easy ways to do more damage.
throw20102010 8y ago
Possibly, but the pilots would have to screw up as well. You typically tune in the ILS when you're expecting to pick up the approach. It's not like you set the ILS frequency hours before landing and just follow the first signal that pops up. So if you do follow a malicious signal, it's going to be few miles away from the airport at the furthest. However, ILS is becoming less used because it requires maintenance of ground systems. GPS approaches could also be spoofed, but would be a more sophisticated attack. But with GPS navigation you aren't tuning radio frequencies in your nav equipment so there's probably more chances to fool a pilot (you could drag them much further away from the airport if you started spoofing GPS further out). However, ALL instrument approaches have minimum visual altitudes, and the lowest I'm aware of is 200 ft above the ground. If you can't see the airport by the time you get down to the minimum altitude you execute a missed approach procedure- basically you climb and navigate to another waypoint to restart the approach or to hold. Additionally, all aircraft must have barometric altimeters as required equipment- no amount of radio spoofing can fool them. So in an ideal world an attack would go like this: the pilot follows the malicious approach, notices that they are at the minimum altitude, looks for the airport but doesn't see it (or sees it a few miles away), then executes a missed approach- no crash. There aren't too many tight approaches that could make you crash by being off by a mile. To get around this you would need to spoof either the pitot-static (pressure sensing) system, or the pilot's altimeter setting. You could only spoof the pitot-static system by sabatoge on the ground, and you can only realistically spoof the altimeter setting by pretending to be ATC on the radio- at which point the real ATC would correct whatever you said and get real suspicious. Of course, given that instrument landings are the highest workload portion of a flight, pilots get distracted. Even if they would normally catch on to the fact that they aren't on the correct approach, you might cause a few crashes by pilots that aren't on top of their game. Edit to add one more thing: Your plane is tracked by airborne surveillance as well, and if you claim to be at a waypoint and that doesn't match what ATC has on their scope they will warn you. So you'd have to also spoof a surveillance signal at the correct location while blocking the real planes signal to keep ATC from noticing.
- tgsovlerkhgsel 8y ago
  > However, ALL instrument approaches have minimum visual altitudes, and the lowest I'm aware of is 200 ft above the ground. https://en.wikipedia.org/wiki/Instrument_landing_system#ILS_categories https://en.wikipedia.org/wiki/Instrument_landing_system#ILS_... claims "<50 ft" decision height for CAT IIIb.