4 ms·

I think this only helps against relay attacks. To use the key to open the door the owner probably has to take the fob out of the pouch and then replay attacks m

I think this only helps against relay attacks. To use the key to open the door the owner probably has to take the fob out of the pouch and then replay attacks might be possible.

exabrial 5y ago
I still don't understand I guess how the pouch mitigates anything
- jcrawfordor 5y ago
  Relay attacks seem to be in use in the wild by sophisticated car thiefs, although I'm not sure how commonly. Given general trends, it's probably more common in Europe than in the US. More to your question though, the issue is that proximity key systems rely on the limited radio transmission range. If a thief uses something like an SDR to "amplify" or repeat the transmissions, they can get the car to think the key is much closer than it is... and potentially unlock the car in your driveway by "using" your key fob inside your house. A faraday pouch makes this very difficult by significantly attenuating the signal from the key fob.
- chiph 5y ago
  I'm assuming it attenuates the signal so that someone parked nearby has a more difficult time capturing the code. Downside is you can't use your remote start from inside the house anymore - you'll have to be very close before the remote will work (which raises the question of what good is having a remote if you're close enough to just use the physical key). But with the faraday pouch, at least the car won't have been stolen. For the MITM attacks on the modern proximity car keys, drop your fob into a metal tin (like the Danish Butter Cookie ones) when you walk in the house to block the signal. https://www.schneier.com/blog/archives/2017/11/man-in-the-midd_8.html https://www.schneier.com/blog/archives/2017/11/man-in-the-mi...
- invalidator 5y ago
  Some cars unlock when you're close, no button presses required. Relay attacks let the thieves use the keyfob inside your house by relaying the signal. A faraday pouch prevents this. It's not related to replay attacks on a traditional push-to-unlock keyfob.
- rmetzler 5y ago
  A faraday cage or faraday pouch blocks electric radio. For example a cellphone will not be able to communicate with the base station if you wrap it aluminium foil and the new car fobs work similar. The fob just needs to be in close distance to the car for someone to open the door or starting the car. A relay attack puts two radio devices between the car fob and the car, so thieves can open and start a car just by relaying the radio signal to the car fob behind the closed door. A replay attack will record the radio signals transmitted between fob and car and just replay them. And both attacks are absolutely possible. You can find videos on youtube for both.

I think this only helps against relay attacks. To use the key to open the door the owner probably has to take the fob out of the pouch and then replay attacks might be possible.

exabrial 5y ago

I still don't understand I guess how the pouch mitigates anything

jcrawfordor 5y ago
Relay attacks seem to be in use in the wild by sophisticated car thiefs, although I'm not sure how commonly. Given general trends, it's probably more common in Europe than in the US. More to your question though, the issue is that proximity key systems rely on the limited radio transmission range. If a thief uses something like an SDR to "amplify" or repeat the transmissions, they can get the car to think the key is much closer than it is... and potentially unlock the car in your driveway by "using" your key fob inside your house. A faraday pouch makes this very difficult by significantly attenuating the signal from the key fob.
chiph 5y ago
I'm assuming it attenuates the signal so that someone parked nearby has a more difficult time capturing the code. Downside is you can't use your remote start from inside the house anymore - you'll have to be very close before the remote will work (which raises the question of what good is having a remote if you're close enough to just use the physical key). But with the faraday pouch, at least the car won't have been stolen. For the MITM attacks on the modern proximity car keys, drop your fob into a metal tin (like the Danish Butter Cookie ones) when you walk in the house to block the signal. https://www.schneier.com/blog/archives/2017/11/man-in-the-midd_8.html https://www.schneier.com/blog/archives/2017/11/man-in-the-mi...
invalidator 5y ago
Some cars unlock when you're close, no button presses required. Relay attacks let the thieves use the keyfob inside your house by relaying the signal. A faraday pouch prevents this. It's not related to replay attacks on a traditional push-to-unlock keyfob.
rmetzler 5y ago
A faraday cage or faraday pouch blocks electric radio. For example a cellphone will not be able to communicate with the base station if you wrap it aluminium foil and the new car fobs work similar. The fob just needs to be in close distance to the car for someone to open the door or starting the car. A relay attack puts two radio devices between the car fob and the car, so thieves can open and start a car just by relaying the radio signal to the car fob behind the closed door. A replay attack will record the radio signals transmitted between fob and car and just replay them. And both attacks are absolutely possible. You can find videos on youtube for both.