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

#101

Post by mikeash » Wed, Dec 05, 2018, 5:34 PM UTC

alistproducer2 wrote: post #97

mikeash wrote: post #74

Earlier quoted context omitted.

The vulnerability is pretty much inherent to the idea. No amount of encryption can protect you from a relay attack. The only foolproof mitigation is to enforce a short round trip time to ensure the fob is actually close to the car, but with the short distances involved that means the fob has to generate and transmit a response within a few nanoseconds.

I disagree. A physical switch on the key itself which opened a circuit to the decryption key would mean the key would need to physically be in the possession of the driver.

“The idea” here refers to having the key operate automatically without having to manipulate it. If you require the driver to push a button on the key, the problem is trivially solved.

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

#102

Post by raisedbyninjas » Wed, Dec 05, 2018, 5:35 PM UTC

alistproducer2 wrote: post #97

mikeash wrote: post #74

Earlier quoted context omitted.

The vulnerability is pretty much inherent to the idea. No amount of encryption can protect you from a relay attack. The only foolproof mitigation is to enforce a short round trip time to ensure the fob is actually close to the car, but with the short distances involved that means the fob has to generate and transmit a response within a few nanoseconds.

I disagree. A physical switch on the key itself which opened a circuit to the decryption key would mean the key would need to physically be in the possession of the driver.

This eliminates all of the convenience of keyless entry/start.

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

#103

Post by 15155 » Wed, Dec 05, 2018, 5:37 PM UTC

dsfyu404ed wrote: post #71

SmellyGeekBoy wrote: post #28

Earlier quoted context omitted.

> I also know people who take the exact opposite approach with their expensive vehicles - they leave the key in plain sight near the front door This seems like the best strategy to me. If you have a desirable vehicle and someone decides to break into your house to get hold of the keys they're going to turn the place upside down trying to find them. If you're in at the time you're also putting yourself in a lot of dan…

Criminals seeking to commit property crime generally go to great lengths to avoid possible confrontations with people. Stealing one more BMW that week is not worth the risk of a 9mm hole in your chest. Breaking into someone's home when you are all but sure they are there (because their car is in the driveway and you want their keys) is just begging for a confrontation. Someone breaking into your house with the expect…

The country of topic is Canada, where the risk of someone protecting their hard-earned property with lethal force does not exist.

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

#104

Post by taw123 » Wed, Dec 05, 2018, 5:37 PM UTC

Latteland wrote: post #99

Tesla recently added a good workaround. They added a setting where you can turn auto unlock or auto start off, which blocks this remote access hack. You have to use your key fob button at least once, say to unlock the car and then it just works wirelessly without further action. My car is unlocked at night but in my garage. If they got in my garage somehow and had the signal repeater they couldn't drive off unless I…

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

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

#105

Post by nkrisc » Wed, Dec 05, 2018, 5:39 PM UTC

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.

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

#106

Post by closeparen » Wed, Dec 05, 2018, 5:41 PM UTC

alistproducer2 wrote: post #97

mikeash wrote: post #74

Earlier quoted context omitted.

The vulnerability is pretty much inherent to the idea. No amount of encryption can protect you from a relay attack. The only foolproof mitigation is to enforce a short round trip time to ensure the fob is actually close to the car, but with the short distances involved that means the fob has to generate and transmit a response within a few nanoseconds.

I disagree. A physical switch on the key itself which opened a circuit to the decryption key would mean the key would need to physically be in the possession of the driver.

That’s what we had 10 years ago.

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

#107

Post by Reedx » Wed, Dec 05, 2018, 5:45 PM UTC

The article recommends putting your fob upstairs or as far away as possible, but that seems like false security.

What's considered a safe distance? How far away can they pick up the signal?

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

#108

Post by ryacko » Wed, Dec 05, 2018, 5:47 PM UTC

mikeash wrote: post #74

retSava wrote: post #37

Earlier quoted context omitted.

Since most car manufacturers seem to be vulnerable (to my knowledge), I assume all or most buy the same COTS keyfob + electronic lock product. Much like Takata airbags or Bosch ECUs. Being a step away from the problem probably helps keep that OEM manufacturer from strapping in and solving it. They don't feel any pain from it.

The vulnerability is pretty much inherent to the idea. No amount of encryption can protect you from a relay attack. The only foolproof mitigation is to enforce a short round trip time to ensure the fob is actually close to the car, but with the short distances involved that means the fob has to generate and transmit a response within a few nanoseconds.

Embedded devices can be laggy at times.

More efficient for the car to estimate the distance and power of the transmitter.

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

#109

Post by wvenable » Wed, Dec 05, 2018, 5:48 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.

That defeats the purpose of the fob. Be easier to put an on/off switch on the fob so you can turn it off at night.

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

#110

Post by whyaduck » Wed, Dec 05, 2018, 5:50 PM UTC

ryandrake wrote: post #78

wsh wrote: post #46

Earlier quoted context omitted.

Yes, it’s a feature, so you don’t have to remove the key from a bag or pocket to enter or start the car. In typical designs, the car continually transmits a low-frequency (e.g., 135 kHz) radio signal to wake up any wireless keys within range. When a key receives this signal, it replies with a VHF (e.g., 315 MHz) signal, and the car unlocks or starts when a door is opened or the start button is pressed. The reply sign…

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.