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BusKill: A kill cord for your laptop

tech.michaelaltfield.net

21–30 of 272 posts

Re: BusKill: A kill cord for your laptop

#21

Can someone explain to me in laymen's terms what this does? It renders the motherboard inoperable? Kills the display? How do you recover from this if you ACCIDENTALLY unplug it?

It locks the screen by executing "xscreensaver-command -lock"

So this is a "kill cord" in the meaning of a jetski, power boat, or treadmill where pulling out the kill cord triggers a fast but nondestructive stop.

Re: BusKill: A kill cord for your laptop

#22

Can someone explain to me in laymen's terms what this does? It renders the motherboard inoperable? Kills the display? How do you recover from this if you ACCIDENTALLY unplug it?

It simply uses udev to identify when the USB device is removed, then executes a linux command of your choosing. In the examples provided, he demonstrates a simple 'lockscreen' and 'shutdown' command.

It's clever, I'll admit, but the name leaves more to be desired with a name like 'buskill'

Re: BusKill: A kill cord for your laptop

#23
post #7

Maybe a smartwatch reading the heart rate of the owner and noticing stimulation could trigger the same functionality as well.

The connection between the smartwatch and the computer would, in practice, be wireless, which is something the author wants to avoid because it's easier to hack without the victim noticing.

Re: BusKill: A kill cord for your laptop

#24

Can someone explain to me in laymen's terms what this does? It renders the motherboard inoperable? Kills the display? How do you recover from this if you ACCIDENTALLY unplug it?

It appears to simply be a USB plug that works with a simple software driver to automatically log out if the USB is unplugged. The scenario is a snatch-and-grab of the laptop while the user is logged in to a highly-secure, high-value online account.

Not something most users likely need but I can imagine some TLAs being interested in something like this, as it looks pretty inexpensive to implement.

Re: BusKill: A kill cord for your laptop

#25

Archive link because the website is down: http://web.archive.org/web/20200102140351/https://tech.micha... I was expecting a "kill switch" destroying the computer, but that's just a thing that switch off your laptop when unplugged. I guess you could also do this with bluetooth, for example.

It appears that it runs a script of your choosing, so you could make it more violent if you wanted (start trashing data, clear cache etc.).

I'd be careful though, as you don't want any "misshaps". It's not likely worth going that far unless you're doing something very sensitive.

Re: BusKill: A kill cord for your laptop

#27

Archive link because the website is down: http://web.archive.org/web/20200102140351/https://tech.micha... I was expecting a "kill switch" destroying the computer, but that's just a thing that switch off your laptop when unplugged. I guess you could also do this with bluetooth, for example.

"Kill cord" is jargon from jetskis, powerboats and treadmills, which often have a cord you attach to your body that cuts power if you are thrown off. [1]

On Linux there is blueproximity [2] that can lock (and if you like, unlock) your computer based on the proximity of a bluetooth device. My personal experience is that Bluetooth is frustratingly unreliable, and this package was no exception. But it's there if you'd like to try it!

[1] https://www.rya.org.uk/knowledge-advice/safe-boating/look-af... [2] http://www.daniloaz.com/en/automatically-lock-unlock-your-sc...

Re: BusKill: A kill cord for your laptop

#29
This is a really neat project but it’s also not really a solution to anything.

First, it doesn’t solve for the scenario of person pointing a gun at you and telling you to access your top secret files for them. That will defeat most forms of security and so if physical access is a concern you probably shouldn’t be logging in at your local coffee shop.

Second, a thief who wants your computer for its monetary value isn’t interested in its contents. Your normal drive encryption and screen timeout restrictions have you covered there. They’re gonna wipe your computer, sell it, and move on.

Institutionally purchased hardware is often equipped with zero-touch provisioning (such as Apple Device Enrollment). These products can be bricked at the hardware level they moment they touch the Internet. They’ll need a new logic board, i.e. new soldered on storage, i.e. they’re not even necessarily worth stealing.

Third, the idea of a magnetic connector’s removal locking or bricking your computer seems awfully inconvenient. That’s gonna be constant false positives without a gain in security.

If you’ve got someone who is after you to obtain your secret company info and knows enough to cause mayhem, you’ve got much bigger problems than whether or not your screen is going to lock. They’re also probably going to use social engineering, targeted malware and spyware, not brute force physical access.

Re: BusKill: A kill cord for your laptop

#30
post #3

SilkRoad guy would of loved this :D

Ross Ulbricht, who was apprehended at a public library while logged in to various accounts. As I recall a plain clothes agent distracted him while others then tackled him. ("would've", not "would of")

This article goes into pretty good detail of his takedown https://www.wired.com/2015/04/silk-road-1/
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