Not sure if there exists any decent counter-measures.
The countermeasures would appear to be:
* blocking the signal using some kind of Faraday cage to store your keys
this relies on changing user behaviour, and not forgetting; kinda removes some of the “convenience” factor
have some kind of disable switch on the key fob, in which case there’s not a huge difference to a regular remote lock/unlock button
* expanding the range of frequencies the key fob uses to try and defeat the range extenders
this likely has regulatory issues, and is probably easy to just update the hardware to cope with (if it doesn’t already)
have the car do some kind of latency measurement on the challenge/response radio message exchange; given that light travels at 1ns per foot (ish!) the car will have to accurately and precisely measure only a few nanos difference, and not suddenly stop working because of nearby radio echoes in a concrete car park (or whatever)
how close to the car is “convenient” to have it unlock automatically? 2 feet (driver standing by car)? 20 feet (kids running ahead to get into car)?
* some kind of “parked up at home” mode so that the first unlock of the day requires a button push
loses some of the convenience again
got to remember to set it (some kind of car locking button again...)
* you could have a second type of “anti-key” that you always leave at home, and when in range of this key the car won’t unlock keylessley
easy target to block in the arms race or car theft
easy to misunderstand as a user
less convenience
Like latency-measurement though I wonder how robust it would be to the vagaries of modern life both in terms of reliability - potential moving parts - and in the face of user expectations - “I keep having to jiggle my keys to open my door” or worse, the dreaded “it doesn’t work!”. Where doesn’t work == doesn’t work how I think it should.
[0] https://en.m.wikipedia.org/wiki/Distance-bounding_protocol
It's only a matter of time till NFC credit cards get read with a high power reader and proxied across a cell connection to steal money from someone hundreds of miles away from the thief.
Then you don't need to worry about the relay-attack, don't need to worry that you car unlocks just because you walk past it, and don't need a steering lock...
I just don't see the appeal even if it worked perfectly. I'd rather pay extra to have it removed.
The 'easy unlocking' feature is idiotically simple to fool as shown. Almost the same as in the late '90s when you could just cycle through the ~2-10k combinations on the fobs.
My advise would be: use the buttons on the key and disable the easy-unlock feature which can usually be done either in the car's settings or at the garage.
Because they break into the house to get the key. It's happened to a few people I know - one time they used a wire hook through a partly opened window.
You might still want keyless entry during the day for routine shopping trips and such but for parking the car overnight you can live without it; and probably sleep a lot better too.
I keep my key in a metalic pouch every night as a countermeasure, works just as well.
However, there's one concern with it - if a thief tries to steal your car using the relay attack and fails, will they break in and try to steal the physical key(which might lead to confrontation and people getting hurt). It's a risk either way.