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Ask HN: Why do we still have replay attacks on our cars?

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Ask HN: Why do we still have replay attacks on our cars?

#1

Post by qmsdfjkc »

So today my car got stolen in front of my house. It was a 2021's Hyundai Tucson.

We clearly see on some cameras in the street that it took less than 1 minute for the thief to take it.

I was not aware that the "replay" attack (as I understand consists simply in listening to my keys signal through my door and replicating it to open and start the car), so my key was not far at all.

So my question is, why is my worthless github account secured by a free android 2FA app which makes replicating attacks impossible, and my 50K€ car secured by the dumbest only-one-forever-the-same key ever?

Is it not possible in the car keys to make some pgpsign-like technology?

(Also I am now aware of the tiktok trend of stealing these Kia and Hyundai car because their security is so easy to abuse)

Re: Ask HN: Why do we still have replay attacks on our cars?

#2

Post by t-3 »

What incentives do automakers have to provide you with a secure product? "Old-school" key ignitions work perfectly fine, so why were they replaced with the obviously-flawed dongle?

How complex would a device have to be to not be trivially defeated by a replay attack? How do you get both ends to reliably communicate without requiring an always-on internet connection in both the dongle and the vehicle to sync timing or some other state? What do you do when the manufacturer no longer exists or doesn't want to pay for servers to enable people to drive "old models"?

Re: Ask HN: Why do we still have replay attacks on our cars?

#5

Post by qmsdfjkc »

t-3 wrote: post #2

What incentives do automakers have to provide you with a secure product? "Old-school" key ignitions work perfectly fine, so why were they replaced with the obviously-flawed dongle? How complex would a device have to be to not be trivially defeated by a replay attack? How do you get both ends to reliably communicate without requiring an always-on internet connection in both the dongle and the vehicle to sync timing or…

Actually the said car has a continuous internet connection, using a sim card, so I guess syncing time wouldn't be that difficult.

Also I remember some Renault Espace in France which had a dongle but then you had to put it somewhere specifically in the car to start it. Adding an NFC/RFID chip could solve part of the problem maybe...

But yes you are right this require maintenance.

Re: Ask HN: Why do we still have replay attacks on our cars?

#7

Post by c7DJTLrn »

t-3 wrote: post #2

What incentives do automakers have to provide you with a secure product? "Old-school" key ignitions work perfectly fine, so why were they replaced with the obviously-flawed dongle? How complex would a device have to be to not be trivially defeated by a replay attack? How do you get both ends to reliably communicate without requiring an always-on internet connection in both the dongle and the vehicle to sync timing or…

>How complex would a device have to be to not be trivially defeated by a replay attack?

Not very.

>How do you get both ends to reliably communicate without requiring an always-on internet connection in both the dongle and the vehicle to sync timing or some other state?

You don't need an Internet connection or server. TLS would do the job just fine.

Re: Ask HN: Why do we still have replay attacks on our cars?

#8

Post by wruza »

t-3 wrote: post #2

What incentives do automakers have to provide you with a secure product? "Old-school" key ignitions work perfectly fine, so why were they replaced with the obviously-flawed dongle? How complex would a device have to be to not be trivially defeated by a replay attack? How do you get both ends to reliably communicate without requiring an always-on internet connection in both the dongle and the vehicle to sync timing or…

How complex would a device have to be to not be trivially defeated by a replay attack?

Around $5 complex (though I lost track of actual prices for few years).

How do you get both ends to reliably communicate

You choose a suitable networking stack and communicate. Secure messaging is a solved problem and doesn’t require “internet”.

Re: Ask HN: Why do we still have replay attacks on our cars?

#9

Post by afiori »

t-3 wrote: post #2

What incentives do automakers have to provide you with a secure product? "Old-school" key ignitions work perfectly fine, so why were they replaced with the obviously-flawed dongle? How complex would a device have to be to not be trivially defeated by a replay attack? How do you get both ends to reliably communicate without requiring an always-on internet connection in both the dongle and the vehicle to sync timing or…

I guess that the major source of complexity would be that both the car need both a transmitter and a receiver, instead on only one each.

But it seems like a risible source of complexity.

Re: Ask HN: Why do we still have replay attacks on our cars?

#10

Post by mecklyuii »

I'm confused.

I thought normal replay attacks are solved and the issue here is more to do to forward they key range close to the car to simulate the car.key being close.

That's what I can't easily just solve if not needing a button on the key which defeats the purpose of the said feature

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