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The attacks to rolling code keys are well known but these keys continue to exist. They allow you to pair a key yourself to the car that you buy online. Partic

The attacks to rolling code keys are well known but these keys continue to exist. They allow you to pair a key yourself to the car that you buy online. Particularly in the US it's quite common that people buy used cars and then another key online that they pair themselves. You won't be able to do this for instance with VAG cars that have KESSY. First of all the immobilizer is paired to the key, secondly the only way to pair a new key to it is via the manufacturer or a licensed dealership because you need a blob from their central server. But the consequence is that people feel like they are being fleeced when they need another key, because it can cost you hundreds of dollars to pair one. In general these types of attacks are much harder in Europe where immobilizers have a legal minimum standard that manufacturers have to meet. On the other hand in the US immobilizer are entirely optional, which has famously led to KIA and Hyundai cars shipping without them and the Kia Boys TikTok phenomenon.

fc417fc802 1y ago
> But the consequence is that people feel like they are being fleeced when they need another key, because it can cost you hundreds of dollars to pair one. Because the ARE being fleeced. It's an artificial dependency on the vendor on the one hand versus a blatantly insecure approach on the other. Secure pairing that can be done by the end user isn't rocket science.
- the_mitsuhiko 1y ago
  It is a bit rocket science because cars stand around. The CAN bus can even be externally accessed if you pop open the right part of the car (common fault are adaptive headlights). It is not as trivial as people make it out to be because cars violate one of the most important principles of having good security: no physical access.
  - fc417fc802 1y ago
    That has nothing to do with secure pairing. It's an entirely orthogonal concern. Any sensitive system on a vehicle is going to be subject to the same thing. I don't think anyone will be surprised if the security is swiss cheese once you pop the hood open or bust a headlight out. Keep in mind that a brick to the window and tearing up the center console will get you physical access to the head unit on most vehicles.
  - IshKebab 1y ago
    It is trivial: 1. Initiate pairing via the entertainment system interface. 2. Use rolling codes. Don't allow rewinding the codes. 3. Add a tiny tiny bit of non-volatile memory in the keys so that batteries can be changed without breaking the key. This is only necessary if the car can't be entered using the physical key, otherwise the user can just open the car with the physical key, turn on the ignition and re-pair the key. I could make a secure system to do this and I'm no crypto genius. (Note this would still be vulnerable to rolljam but that's not a very practical attack, and defeating that is a bit difficult.) To support car hire/share places if they want to prevent users pairing new keys you could allow setting a password on the pairing interface.
    - the_mitsuhiko 1y ago
      That's more or less already how the rolling code based systems work. The problem of course is that if you have access to one of those keys (or use rolljam to get one or more codes) you have enough to get another key added.
      - fc417fc802 1y ago
        That isn't the problem, at least not the major one that lead to this discussion. It's that the algorithm used is broken. It's example number 9001 of why you should never roll your own crypto for a commercial application. (Amusingly example 9002, TETRA radios, was also on the HN frontpage around the same time).
        the_mitsuhiko 1y ago
        First of all they did not roll their own crypto, it's just not the most modern crypto any more. Secondly while this particular permutation of the issue is related to bad crypto, it's cascading a completely different issue which is that it's just fundamentally possible to pair a key with physical access which is easy to get.
        fc417fc802 1y ago
deleted 1y ago
[deleted]
IshKebab 1y ago
But the attack claims to not need access to the car to initiate any kind of pairing sequence...
- the_mitsuhiko 1y ago
  Yes. With rolling codes this vulnerability and similar ones are known for a very long time.
  - IshKebab 1y ago
    Seems to be from 2022. I wouldn't say that is "a very long time".
    - the_mitsuhiko 1y ago
      The fundamental flaws with this approach to keys is known since before 2015, but got a lot of international recognition when people found cheap ways to emulate keys through cheap software defined radios around that time.
      - IshKebab 1y ago
        I don't think so. The Flipper Zero isn't an SDR. What's the earliest reference to this attack you can actually provide?
        the_mitsuhiko 1y ago
        I’m talking about the earliest cases. The earliest references depend on the particular standard of crypto. KeeLoq is a very famous rolling code standard where attacks go back to 2007 and earlier. RollJam is known since 2014 [1]. It was popularized later through a custom device [2]. [1]: https://spencerwhyte.blogspot.com/2014/03/delay-attack-jam-intercept-and-replay.html https://spencerwhyte.blogspot.com/2014/03/delay-attack-jam-i... [2]: https://www.wired.com/2015/08/hackers-tiny-device-unlocks-cars-opens-garages/ https://www.wired.com/2015/08/hackers-tiny-device-unlocks-ca...

fc417fc802 1y ago

> But the consequence is that people feel like they are being fleeced when they need another key, because it can cost you hundreds of dollars to pair one. Because the ARE being fleeced. It's an artificial dependency on the vendor on the one hand versus a blatantly insecure approach on the other. Secure pairing that can be done by the end user isn't rocket science.

the_mitsuhiko 1y ago
It is a bit rocket science because cars stand around. The CAN bus can even be externally accessed if you pop open the right part of the car (common fault are adaptive headlights). It is not as trivial as people make it out to be because cars violate one of the most important principles of having good security: no physical access.
- fc417fc802 1y ago
  That has nothing to do with secure pairing. It's an entirely orthogonal concern. Any sensitive system on a vehicle is going to be subject to the same thing. I don't think anyone will be surprised if the security is swiss cheese once you pop the hood open or bust a headlight out. Keep in mind that a brick to the window and tearing up the center console will get you physical access to the head unit on most vehicles.
- IshKebab 1y ago
  It is trivial: 1. Initiate pairing via the entertainment system interface. 2. Use rolling codes. Don't allow rewinding the codes. 3. Add a tiny tiny bit of non-volatile memory in the keys so that batteries can be changed without breaking the key. This is only necessary if the car can't be entered using the physical key, otherwise the user can just open the car with the physical key, turn on the ignition and re-pair the key. I could make a secure system to do this and I'm no crypto genius. (Note this would still be vulnerable to rolljam but that's not a very practical attack, and defeating that is a bit difficult.) To support car hire/share places if they want to prevent users pairing new keys you could allow setting a password on the pairing interface.
  - the_mitsuhiko 1y ago
    That's more or less already how the rolling code based systems work. The problem of course is that if you have access to one of those keys (or use rolljam to get one or more codes) you have enough to get another key added.
    - fc417fc802 1y ago
      That isn't the problem, at least not the major one that lead to this discussion. It's that the algorithm used is broken. It's example number 9001 of why you should never roll your own crypto for a commercial application. (Amusingly example 9002, TETRA radios, was also on the HN frontpage around the same time).
      - the_mitsuhiko 1y ago
        First of all they did not roll their own crypto, it's just not the most modern crypto any more. Secondly while this particular permutation of the issue is related to bad crypto, it's cascading a completely different issue which is that it's just fundamentally possible to pair a key with physical access which is easy to get.
        fc417fc802 1y ago

deleted 1y ago

[deleted]

IshKebab 1y ago

But the attack claims to not need access to the car to initiate any kind of pairing sequence...

the_mitsuhiko 1y ago
Yes. With rolling codes this vulnerability and similar ones are known for a very long time.
- IshKebab 1y ago
  Seems to be from 2022. I wouldn't say that is "a very long time".
  - the_mitsuhiko 1y ago
    The fundamental flaws with this approach to keys is known since before 2015, but got a lot of international recognition when people found cheap ways to emulate keys through cheap software defined radios around that time.
    - IshKebab 1y ago
      I don't think so. The Flipper Zero isn't an SDR. What's the earliest reference to this attack you can actually provide?
      - the_mitsuhiko 1y ago
        I’m talking about the earliest cases. The earliest references depend on the particular standard of crypto. KeeLoq is a very famous rolling code standard where attacks go back to 2007 and earlier. RollJam is known since 2014 [1]. It was popularized later through a custom device [2]. [1]: https://spencerwhyte.blogspot.com/2014/03/delay-attack-jam-intercept-and-replay.html https://spencerwhyte.blogspot.com/2014/03/delay-attack-jam-i... [2]: https://www.wired.com/2015/08/hackers-tiny-device-unlocks-cars-opens-garages/ https://www.wired.com/2015/08/hackers-tiny-device-unlocks-ca...