Thieves boosting signal from key fobs inside homes to steal vehicles • Hacker News Board

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#151

Post by reaperducer » Wed, Dec 05, 2018, 6:39 PM UTC

extrapickles wrote: post #143

Car makers should use frequency/channel hopping rather than time of flight until doing time of flight gets cheaper. The car and fob would also broadcast on frequencies/channels that are not in the preshared set to detect someone trying to amplify. The hopping pattern should be derived from a good cryptographic protocol that also contains mutual attestation.

How would that affect battery life?

To you and me, changing the batteries in a key fob isn't a big deal. But more than once I've seen people walk into the auto dealer's repair center because their fob stopped working, and all the tech did to repair it is replace the battery.

(If you think that sounds stupid, I work in healthcare, and we have employees who spend a surprising amount of time teaching people how to put AA batteries in their blood pressure and other medical gadgets.)

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#152

Post by ghaff » Wed, Dec 05, 2018, 6:39 PM UTC

jwr wrote: post #123

A good solution to that problem are UWB radios with timestamping (like the Decawave DW1000), which let you measure the time it takes for the signal to travel. You can then place physical limits on the proximity, rather than assuming that a strong radio signal means proximity. Coupled with a cryptographic authentication protocol these solve the issue quite nicely.

It looks like the chips are about $10 each. That's quantity 1 but it's also just the radio IC. It's not immediately obvious what the power draw would look like in an application like this as the sleep mode draws far less power than when it's operating. There is an open source project based on the chip. https://github.com/lab11/polypoint

What I'd really like to be able to do is to wirelessly tether a Tile-like small long battery life device to a band (or watch) I wear with user configurable distance settings but it doesn't look like the tech is quite there today. UWB does seem to be the current approach you'd take though.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#153

Post by stronglikedan » Wed, Dec 05, 2018, 6:41 PM UTC

jamescostian wrote: post #116

nkrisc wrote: post #105

I imagine improvements to the key fob could be made that would require a mechanical coupling with the car in order to start it. That would circumvent this attack.

I'm not sure if this is a joke about old keys being better, but I'd argue you could have the benefits of new keys and old keys combined if you just made it so that new keys have to be inserted into some compartment inside of cars, where they are authenticated by those cars. You can imagine a fob with a USB that has a different authentication code than the wireless one it sends out, and unless the USB is plugged into…

But then my mom would have to dump out her purse every time she wanted to unlock her car.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#154

Post by paulie_a » Wed, Dec 05, 2018, 6:41 PM UTC

nine_k wrote: post #140

I think convenience here is fundamentally at odds with security. The convenience here is that the system requires no confirmation from the driver, no physical interaction with buttons, handles, keys, etc. The driver just opens the door and starts the engine. This allows for a trivial remote sniff-and-replay attack, not unlike copying a key temporarily. I bet not having a lock on the door would be even more convenient…

Leaving a car unlocked is sometimes safer, while not foolproof it reduces the likelihood of getting your window smashed to loot the vehicle for valuables (and non valuable items)

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#155

Post by seniorsassycat » Wed, Dec 05, 2018, 6:44 PM UTC

Another commentor describes the key handshake. The car emits a high frequency wake up signal, the key receives the signal and emits a low frequency unlock code. It is hard to restrict the time of the unlock code because it's low frequency limits the accuracy of your clock.

Could you Honeypot the cars wake up signal? If the car detects a delayed broadcast of it's wake up signal it could trigger an alarm or at disable keyless entry. The high frequency signal will have lower tolerances for a timing check.

Or car makers can provide Honeypot keys. If the key receives a wake up signal it can alert the owner and disable keyless entry. The owner would put the Honeypots where they don't want their keys to activate.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#156

Post by taw123 » Wed, Dec 05, 2018, 6:44 PM UTC

Latteland wrote: post #112

taw123 wrote: post #104

Earlier quoted context omitted.

A motion sensor in the remote would also work and maintain the convenience.

Unless it was in my pocket and I was walking around with it, which I do every day.

True, the solution isn't perfect. Just brainstorming ideas that can potentially be coupled with other layers of security. The advantage of the idea is it doesn't rely on the user activating a secure mode or knowing about the vulnerability. The protection is automatic when you're asleep. Arguably if you're walking, not a large amount of that time is near your front door - although I understand your location may still be predictable.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#157

Post by bootlooped » Wed, Dec 05, 2018, 6:46 PM UTC

oh_sigh wrote: post #146

Latteland wrote: post #112

Earlier quoted context omitted.

Unless it was in my pocket and I was walking around with it, which I do every day.

Why would a motion sensor not sense motion in your pocket?

I think they're saying the thieves could still execute the signal boosting attack while the car owner is walking around with their keys.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#158

Post by cronix » Wed, Dec 05, 2018, 6:46 PM UTC

nkrisc wrote: post #105

I imagine improvements to the key fob could be made that would require a mechanical coupling with the car in order to start it. That would circumvent this attack.

A simple on/off button on the fob would work, and probably extend the battery life by a few years.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#159

Post by taw123 » Wed, Dec 05, 2018, 6:47 PM UTC

oh_sigh wrote: post #146

Latteland wrote: post #112

Earlier quoted context omitted.

Unless it was in my pocket and I was walking around with it, which I do every day.

Why would a motion sensor not sense motion in your pocket?

The parent is rightly pointing out that it could yield an unintended RF activation.

Re: Thieves boosting signal from key fobs inside homes to steal vehicles

#160

Post by blacksmith_tb » Wed, Dec 05, 2018, 6:50 PM UTC

whyaduck wrote: post #110

ryandrake wrote: post #78

Earlier quoted context omitted.

This is insane. Please tell me this is an option that non-insane consumers can get their car without. Fortunately I drive an old car so this does not affect me—yet. If I ever have to replace mine, this looks like yet-another-misfeature I’ll have to look out for to avoid.

On many models keyless entry and remote start are options, rather than standard. If you park in a garage at night, then this particular attack isn't much of an issue.

I'm sure you didn't intend it that way, but "let them park in their garages" seems to imply the hoi polloi who don't have covered parking deserve to have their vehicles stolen...