I meant they should have failsafes in place so jamming isn’t an effective attack.
A simple analogy is locks. Instead of making lock picking kits illegal, design better locks to increase the time and knowledge needed to defeat a lock.
Car remote unlock design is lazy: you push the button and it generates a key, which is invalidated when used. There’s nothing more complex here than a defined order. To protect against that, add a time element (like TOTP in Google Authenticator). Your fob and car would keep time independently, so an attacker would have a very narrow window (i.e. under a second) to attack the car, if that. Resync the fob with the car after a successful challenge/response process so they don’t drift too much, and allow resyncing with physical entry.
Car companies should pay when their laziness leads to compromise.
Totps only works when both source and recipient are synced pretty much identically in time. Meaning the car and fob would need to receive their time from an external source.
Not that hard in many places, just grab the time from a radio broadcast. But what happens when that broadcast isn’t available? You fall back on a known inaccurate time. I’ve seen cars with a bum RTC chip, which lost about a minute a day. That would be enough to kill off this kind of system.
Not to mention that an external time source would be larger, cost more, require more power, and would be vulnerable to brand new attacks.
There is no perfect system. Take your physical lock for instance, there is no unpickable lock. They just plum don’t exist.
I meant they should have failsafes in place so jamming isn’t an effective attack.
A simple analogy is locks. Instead of making lock picking kits illegal, design better locks to increase the time and knowledge needed to defeat a lock.
Car remote unlock design is lazy: you push the button and it generates a key, which is invalidated when used. There’s nothing more complex here than a defined order. To protect against that, add a time element (like TOTP in Google Authenticator). Your fob and car would keep time independently, so an attacker would have a very narrow window (i.e. under a second) to attack the car, if that. Resync the fob with the car after a successful challenge/response process so they don’t drift too much, and allow resyncing with physical entry.
Car companies should pay when their laziness leads to compromise.
Totps only works when both source and recipient are synced pretty much identically in time. Meaning the car and fob would need to receive their time from an external source.
Not that hard in many places, just grab the time from a radio broadcast. But what happens when that broadcast isn’t available? You fall back on a known inaccurate time. I’ve seen cars with a bum RTC chip, which lost about a minute a day. That would be enough to kill off this kind of system.
Not to mention that an external time source would be larger, cost more, require more power, and would be vulnerable to brand new attacks.
There is no perfect system. Take your physical lock for instance, there is no unpickable lock. They just plum don’t exist.