OpenSesame – A device that can open fixed-code garage doors in seconds • Hacker News Board

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#101

Post by twanvl » Fri, Jun 05, 2015, 11:43 AM UTC

mrb wrote: post #66

Cymen wrote: post #50

Earlier quoted context omitted.

Somewhat of a tangent, but I am concerned about the MITM attack on car locks [1]. This kind of attack is being used in my neighborhood in Oakland, California and no doubt other places. I read the reports of "someone is breaking into my car but no windows/locks are broken". Then a couple other people on NextDoor chime in with the same thing and one person reports a woman who is walking around the neighborhood and appe…

Yeah, a car's passive entry system can definitely be exploited by relay attacks. Here is an academic group who demonstrated it: https://eprint.iacr.org/2010/332.pdf The most obvious way to mitigate is to have the car require the key to send the first bit of the response at most N nanoseconds after the last bit of the challenge is sent over the air. Because of the speed of light this assures the key is within a certai…

You don't need to compute the challenge in N nanoseconds. Instead, the car could send a challenge, the key can compute it in however much time it likes. Then the car sends a one time pad, the key receives it and xors the otp with the challenge's response. Then it sends that.

The cryptographic challenge makes it secure, the XORed one-time-pad allows for fast measurement of the round trip time.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#102

Post by logfromblammo » Fri, Jun 05, 2015, 1:57 PM UTC

vacri wrote: post #79

logfromblammo wrote: post #62

Earlier quoted context omitted.

My parents have two Papillons that bark frantically if a butterfly enters the airspace of their house. Sit on the couch? Bark. Stand up from the couch? Bark. Phone rings? Bark. Television channel changes? Bark. Doorbell rings? BARKBARKBARKBARKBARKBARKYOURHEADASPLODE! In order to gauge the severity of any potential threat, you have to time the barking interval. If it lasts longer than three minutes, there may be armed…

Sounds like the cure is worse than the disease...

Not really. If you're looking for home security, get a terrier. They are high on loyalty and low on fear, so if they are barking, there's probably a non-packmate animal around. Some were bred to chase badgers down into their holes and kill them, after all. They're anything but timid.

Pit Bulls are terriers, and one reason they are so popular for lower-income city-dwellers is the manageable danger they present to unauthorized, non-packmate intruders in their range. You do not burgle a house with a Pit Bull or Staffordshire in it, period. And you think twice or thrice for any other type of dog. The fences, warning signs, food, vets, and boarding are very often cheaper in the long run than professional alarm system monitoring or contents replacement insurance.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#103

Post by nickbauman » Fri, Jun 05, 2015, 2:18 PM UTC

patcheudor wrote: post #90

nickbauman wrote: post #53

Earlier quoted context omitted.

A friend who lives in a wealthy neighborhood here had their garage broken into electronically more than 10 years ago. So clearly some people have known about it for a while. The local police claim the thief probably "listened" to their garage door opener open the door at least once to get in, as opposed to brute forcing it.

It's not uncommon for thieves to go to open houses in nice neighborhoods when a property is for sale & copy the dip-switch codes. This also happens when homes are under construction. No one ever thinks about changing their garage door opener code.

I hadn't even thought about that breach vector! In this case they'd been living there for quite a while.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#104

Post by 15155 » Fri, Jun 05, 2015, 3:05 PM UTC

logfromblammo wrote: post #65

unoti wrote: post #4

Which should I consider more insecure: my garage door, or the deadbolt on my front door? I wonder how commonly lock picking is used in crimes. I've picked a lock before myself, but I have no real idea how effective locks are in stopping people that want to commit house thefts. I expect an automated garage door opener is much easier to use than a lock pick though, and probably easier to produce and distribute than loc…

No housebreaker with an ounce of brains would use a lock pick before trying a bump key first. The locks on your house are almost certainly bumpable. The locks at your workplace might be more secure. That's fine, though. If you make the lock on your front door more secure, the weak point is now the latching mechanism, the door frame, or the door itself. Or perhaps it is your sliding patio door, that can be levered. Ma…

> The locks on your house are almost certainly bumpable

2-sided Abloy Protec 2 elite, locking-thumb-turn deadbolt on a metal door with a metal frame.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#105

Post by patcheudor » Fri, Jun 05, 2015, 3:38 PM UTC

nickbauman wrote: post #103

patcheudor wrote: post #90

Earlier quoted context omitted.

It's not uncommon for thieves to go to open houses in nice neighborhoods when a property is for sale & copy the dip-switch codes. This also happens when homes are under construction. No one ever thinks about changing their garage door opener code.

I hadn't even thought about that breach vector! In this case they'd been living there for quite a while.

It's also pretty common for garage door installers / builders to either not change the default config or use the same one or pattern for every home. We were amongst the first to build a house in a new sub in our area so we'd go for walks around the neighborhood while the homes were being built and would go through them and of course I'd always look at the codes. The primary builder in the sub set the dip switches to the number address of the house. That provided a nice geeky / awkward way for me to introduce myself to my neighbors by opening their garage doors for them.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#106

Post by CONTRARlAN » Fri, Jun 05, 2015, 6:20 PM UTC

c22 wrote: post #96

CONTRARlAN wrote: post #93

Earlier quoted context omitted.

Which is only as secure as the door frame it goes into, which usually means: pretty insecure. Still, I agree with the premise that it's about assumptions, and if people can be made to realize that their garage door openers are inherently pretty insecure, and feel that that presents a substantial, then there's a market there. But until it becomes a problem that's common enough for media outlets to scare people about i…

> Which is only as secure as the door frame it goes into, which usually means: pretty insecure. But the door frame/deadbolt is still more secure than the remote controlled garage door because abusing the former mode of entry is more likely to draw concern from passers by and leaves a permanent record of your passage.

I think that's one valid way of looking at it, and many technically-inclined people would be inclined to agree, I'd imagine.

But another way of looking at it, and one I suspect most non-technical people would, is that it just takes one motivated person of roughly-average strength to break a doorframe. It takes someone with fairly uncommon technical sophistication to make one of these devices.

Once someone mass-produces them and sells them in real volume that perception could flip, but right now I'm far more concerned about a flimsy doorframe–which leads to where I live and sleep–than I am about someone rigging up a way to open my garage door–which only gets them into a detached garage where insured stuff is kept. The odds of a break-in being by force (whether against a door frame or a window) are just vastly higher.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#107

Post by sitkack » Sat, Jun 06, 2015, 9:40 PM UTC

mrb wrote: post #18

Three weeks ago I reverse-engineered my garage door opener wireless protocol. I probed the remote's PCB with a Saleae logic analyzer and found it was a 12-bit code ASK-modulated at 390 MHz with bits encoded as sequences of 10 kHz and 20 kHz pulses. I bought a $13 spare remote to hack it and control the RF transmitter section from my computer through an FT232 sending the ASK signal. I just cut off the digital signal t…

Did stuff like this when was a kid, but just used a binary counter hooked into the switches on the replacement remote. What I really wanted as a huge RF amplifier so I could broadcast the signal 5+ miles in all directions.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#108

Post by Houshalter » Sun, Jun 07, 2015, 11:43 AM UTC

logfromblammo wrote: post #65

unoti wrote: post #4

Which should I consider more insecure: my garage door, or the deadbolt on my front door? I wonder how commonly lock picking is used in crimes. I've picked a lock before myself, but I have no real idea how effective locks are in stopping people that want to commit house thefts. I expect an automated garage door opener is much easier to use than a lock pick though, and probably easier to produce and distribute than loc…

No housebreaker with an ounce of brains would use a lock pick before trying a bump key first. The locks on your house are almost certainly bumpable. The locks at your workplace might be more secure. That's fine, though. If you make the lock on your front door more secure, the weak point is now the latching mechanism, the door frame, or the door itself. Or perhaps it is your sliding patio door, that can be levered. Ma…

My family owns an abandoned house and it's been broken into like 10 times by thieves looking for stuff to steal. I believe they stole some guns and fireworks, and just trashed everything else.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#109

Post by ssharp » Mon, Jun 08, 2015, 1:44 PM UTC

saidajigumi wrote: post #75

mrb wrote: post #18

Three weeks ago I reverse-engineered my garage door opener wireless protocol. I probed the remote's PCB with a Saleae logic analyzer and found it was a 12-bit code ASK-modulated at 390 MHz with bits encoded as sequences of 10 kHz and 20 kHz pulses. I bought a $13 spare remote to hack it and control the RF transmitter section from my computer through an FT232 sending the ASK signal. I just cut off the digital signal t…

> But there is probably no interest... FWIW, this sounds like a hook around building a business for "next-gen" garage door openers. Security, quality of build, and convenience are among the factors that could be pitched to early adopters. Heck, this even feels like something that the right small team could work into a really sharp Kickstarter pitch, if so inclined. One tricky problem is that garage door openers tend…

Around 10 years ago, I bought a house that had two garage doors and each door had it's own separate remote and each were the insecure fixed-code kind.

I was able to easily wire-up a replacement receiver to the opener unit that allowed me to update them them to rolling code systems that were more secure and would allow me to control both on one remote. I remember it being a bit clunky, in that I had to plug the receiver into a wall outlet and run a wire back to the opener unit (I think most newer homes put in outlets in the ceiling for the opener to plug into, but this one was directly wired into a ceiling box), but it wasn't very hard to install and was a lot better than having to replace the entire unit!

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#110

Post by logfromblammo » Mon, Jun 08, 2015, 2:33 PM UTC

15155 wrote: post #104

logfromblammo wrote: post #65

Earlier quoted context omitted.

No housebreaker with an ounce of brains would use a lock pick before trying a bump key first. The locks on your house are almost certainly bumpable. The locks at your workplace might be more secure. That's fine, though. If you make the lock on your front door more secure, the weak point is now the latching mechanism, the door frame, or the door itself. Or perhaps it is your sliding patio door, that can be levered. Ma…

> The locks on your house are almost certainly bumpable 2-sided Abloy Protec 2 elite, locking-thumb-turn deadbolt on a metal door with a metal frame.

You, good sir or madam, are an outlier.