LWN: Comments on "Garrett: Wifi deauthentication attacks and home security"

Garrett: Wifi deauthentication attacks and home security

BlueLightning — Tue, 07 Jan 2020 19:48:20 +0000

You may want to update your understanding, it appears the law previously required *registration* (not really a license) now makes that part optional:

https://ico.org.uk/your-data-matters/domestic-cctv-system...

Of course you do still have a number of obligations.

Garrett: Wifi deauthentication attacks and home security

Wol — Tue, 07 Jan 2020 16:56:13 +0000

My understanding of the law is that it is (maybe) okay to video your neighbour's property WITH THEIR PERMISSION. It is NOT okay to video public areas without a licence.

Our church's video accidentally strayed over our neighbour's property which actually solved a crime, so the police don't worry too much about the rules when it suits them :-) A little old lady withdrew some cash and was mugged outside her house. The bank atm camera caught someone loitering near where she drew the cash, and when the police checked the church cameras had caught the same person next to the mugging. Pretty much a slam dunk, and because they did it quickly, they raided the suspect and actually found the cash I believe.

Cheers,
Wol

Garrett: Wifi deauthentication attacks and home security

BlueLightning — Tue, 07 Jan 2020 12:16:11 +0000

> would necessarily be looking over it into public space as well, which is not allowed

I'm pretty sure it is allowed under UK law, based on what I have read it just requires that you comply with the GDPR and Data Protection Act; it may be advisable to register with the ICO as a "Data Controller". You may of course decide that is all more hassle than it is worth. Many camera/recording systems have privacy filters so you can blur/block out regions of the recorded image; typically this is used to avoid capturing other people's *private* property but you could theoretically use it to restrict the coverage to your property alone whilst having the camera position still be reasonable, but depending on the layout of your property and where you want to place the camera that may still be rather difficult.

Garrett: Wifi deauthentication attacks and home security

nix — Tue, 07 Jan 2020 11:35:58 +0000

This prohibition has interesting interactions with police policy in some parts of the UK. My garden wall was recently demolished by someone who drove into it in the middle of the night, but the police refuse to even issue a crime number without the car numberplate (conveniently buffing their crime stats by refusing to notice crimes: they probably have to do this because their funding is so stretched, but it's still aggravating). Obviously I'm not staying up looking out of my kitchen window in the middle of the night just in case someone crashes a car into the wall, so I don't have the numberplate. I was tempted to set up a camera to catch the numberplate in case this happened again, but obviously something looking at my garden wall would necessarily be looking over it into public space as well, which is not allowed. Whoops!

(I wouldn't care, but my insurance won't pay out without a crime number... bah.)

Garrett: Wifi deauthentication attacks and home security

rgmoore — Fri, 03 Jan 2020 15:40:09 +0000

The USA squares this particular circle by saying there is no right to privacy in a public place, and the property owner gets to set the rules in private places. In mjg's case, this would mean the landlord would decide whether it was OK to use video doorbells. My guess is that most landlords would decide in favor of the video doorbell owners, seeing their use as not fundamentally different from using the peephole viewer already installed in their apartment door.

Garrett: Wifi deauthentication attacks and home security

Wol — Fri, 03 Jan 2020 14:38:48 +0000

Ah ... the joys of opening mouth before engaging brain (or reading the article, in this case).

There are TWO sub-threads here. The - clearly improper - use of this technology to interfere with the *security* aspects of cctv, and the "Who is illegal, the operator or the jammer" aspect of videoing communal areas.

mjg is fully justified in not wanting to be filmed/recorded when he is in a communal area outside his apartment, but I'm fully justified in wanting my doorbell to record people who are on my property.

How do you square the circle?

Cheers,
Wol

Garrett: Wifi deauthentication attacks and home security

Karellen — Thu, 02 Jan 2020 23:45:48 +0000

Well, I guess any burglars using such technology had better try and take some steps to not get caught by law enforcement then...

Garrett: Wifi deauthentication attacks and home security

rahvin — Tue, 31 Dec 2019 20:20:49 +0000

Easiest way to handle that is to have two recorders. One of the NVR boxes, and a zoneminder instance that writes the video to a network drive. They'll take the NVR but won't realize there is a second set of data on the server.

Garrett: Wifi deauthentication attacks and home security

SEJeff — Mon, 30 Dec 2019 18:28:45 +0000

This is why I got the doorbird video doorbell. It supports wireless, but also supports PoE cat5/6. I just drilled through my wall and installed it. Bonus that it has a documented http api and doesn't require cloud access to work.

Garrett: Wifi deauthentication attacks and home security

martin.langhoff — Mon, 30 Dec 2019 14:43:05 +0000

Yeah this technique is cool, but RF interference seems a much more practical and effective strategy. It doesn't take a lot.

Garrett: Wifi deauthentication attacks and home security

pizza — Mon, 30 Dec 2019 02:57:45 +0000

Interference on radio bands is one of the few things the FCC has always come down hard on, and that authority predates the CFAA by many decades.

Back in the 2014-2015 timeframe, the FCC levied about $1.4 million in fines to hotels and conference center wifi providers that were actively interfering (using this same deauth technique) with private hotspots.

Garrett: Wifi deauthentication attacks and home security

Wol — Sun, 29 Dec 2019 22:26:42 +0000

But IS it lawful here?

In the UK it would be a very grey area. Certainly my Ring is not supposed to reach beyond my driveway. Due to the layout of my house it's hard to stay legal, but my neighbour knows about it and is actually happy in that it covers her drive too. But straying further to cover the pavement is definitely illegal without a licence.

Here, as it's a private apartment block, I don't know what the position in the UK would be, but laws saying it's illegal to cover a public place wouldn't apply because legally it's not public.

Cheers,
Wol

Garrett: Wifi deauthentication attacks and home security

quotemstr — Sun, 29 Dec 2019 19:46:54 +0000

Deliberately interfering with other people's lawfully-run networks ought to be considered a violation of the CFAA.

Garrett: Wifi deauthentication attacks and home security

Wol — Sun, 29 Dec 2019 18:03:49 +0000

Especially if it's something like a Pi with a 128GB memory stick. Or if it's the router ... why would they nick that unless they realised it had this hanging off it.

Cheers,
Wol

Garrett: Wifi deauthentication attacks and home security

mpr22 — Sun, 29 Dec 2019 16:55:26 +0000

And if you're likely to be the target of the rare ones who would do so, you probably need to hire actual security guards anyway.

Garrett: Wifi deauthentication attacks and home security

eru — Sun, 29 Dec 2019 16:40:49 +0000

The burglar can steal (or destroy) the hard drive

Yes, but you can hide it. Burglars are in a hurry, and are not going to comb every inch of your house for hidden servers.

Garrett: Wifi deauthentication attacks and home security

johill — Sun, 29 Dec 2019 08:01:48 +0000

They don't, this doesn't suddenly delete the information, it just makes devices get disconnected in that particular moment.

Garrett: Wifi deauthentication attacks and home security

flussence — Sat, 28 Dec 2019 17:30:54 +0000

It wouldn't have to be anywhere near this sophisticated, consumer wifi signals are fragile and weak at the best of times. Just have a low-tech battery-powered thing screaming noise or harmonics into the 2.4/5GHz band.

I've heard a spark gap transmitter is enough to ruin it for everyone, but I don't have my old electronics experiment set any more to try it…

OT: 36c3 coverage

brunowolff — Sat, 28 Dec 2019 15:19:44 +0000

The C3 congress and LCA are my favorite tech conferences and I now look through their talks each year and recommend them to people.

jamming radio

johnjones — Sat, 28 Dec 2019 14:36:25 +0000

this is really nothing very new at all I'm afraid, they even have devices sold that do Wifi, GSM (all flavours LTE etc) and other useful frequency
Nations engage in this behaviour all the time

https://en.wikipedia.org/wiki/Radio_jamming

with regards to WiFi and deauth it's a OLD problem and deauth protection is built into Linux

Ring might well not be using Linux...

OT: 36c3 coverage

bangert — Sat, 28 Dec 2019 12:57:19 +0000

Perhaps the editors may look into making coverage of the then 37c3 conference a priority. I know it's in the holidays, but perhaps some lwn-associated reporters are making their way down to it anyway?

The density of interesting presentations just seems staggeringly high - so much as a couple of the latest news items seem to coincide with / be inspired by / worthy of a talk at the conference.

Garrett: Wifi deauthentication attacks and home security

bangert — Sat, 28 Dec 2019 12:50:08 +0000

I wonder how long it would take friends to notice they have to re-add all their gear after they've had a visit by this particularly geeky friend...

Garrett: Wifi deauthentication attacks and home security

NAR — Sat, 28 Dec 2019 11:56:53 +0000

The burglar can steal (or destroy) the hard drive with the local backup too. On the other hand the loss of internet connection might trigger an alarm remotely.

Garrett: Wifi deauthentication attacks and home security

Cyberax — Sat, 28 Dec 2019 10:51:26 +0000

They can also carry a cellphone jammer to make sure alarms can't use backup cellular connection which is pretty standard these days.

My current alarm system uses AES radio precisely because of this - it operates on its own dedicated band with a high-powered transmitter.

As an aside, my first alarm system actually continuously maintained connection with the monitoring company. Cutting the wire immediately triggered it, as did picking up a parallel phone (and you could hear modem-like noises on the line). Alas, I no longer have a wired phone line.

Garrett: Wifi deauthentication attacks and home security

luto — Sat, 28 Dec 2019 05:57:33 +0000

Future? AIUI, this is SOP in Los Angeles. Thieves cut the cable line and then break in.

Garrett: Wifi deauthentication attacks and home security

rgmoore — Sat, 28 Dec 2019 01:02:07 +0000

Which is why, if I have any *security* kit, I want it on a *wired* network ...

It might also be good to keep everything on local storage, or at least maintain it locally until you're sure it's been backed up to the cloud. Just as old-time thieves might start by cutting the phone wires so people and alarm systems couldn't call out, future attacks will likely start by disabling the internet connection.

Garrett: Wifi deauthentication attacks and home security

Wol — Fri, 27 Dec 2019 22:06:07 +0000

I wonder if this is how theives nicked an acquaintance's daughter's Jag. Apparently the Ring showed the Jag on the drive, then showed it being driven off, but there was no video of anyone actually breaking into it ...

Which is why, if I have any *security* kit, I want it on a *wired* network ...

(We have recently acquired a Ring doorbell, but it's so my wife can actually answer the door to delivery drivers etc before they give up and leave, as she can't get to the door quickly ...)

Cheers,
Wol

Garrett: Wifi deauthentication attacks and home security

ms-tg — Fri, 27 Dec 2019 18:10:45 +0000

This is a great post, thanks for sharing it.

Question: how might one instrument and execute this “surveillance self defense” in a practical way? I assume you would carry a suitable device around with you, so a phone or iPod or similar seems ideal — but I don’t know that it’s possible to implement these WiFi packet capture and injection techniques on mainstream phones?