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BusKill: A kill cord for your laptop

tech.michaelaltfield.net

11–20 of 272 posts

Re: BusKill: A kill cord for your laptop

#11
What if someone plugs in a rubber ducky or some other kind of sophisticated USB while you turn your head for just a second?

There are USB devices that are so small, you can barely even see them in the port when plugged in.

Perhaps a hard-to-remove USB plug? (like child-proof plugs you might see in an electrical outlet)

Re: BusKill: A kill cord for your laptop

#12
post #5
post #3

Earlier quoted context omitted.

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")

Other English speakers I know complain about our orthography: bought, caught, draught, etc. But, yet, here we are with a “word” pronounced “of” and spelled “‘ve”! Now that’s awful orthography!

It's not pronounced "of", it's more like "ev", exactly like the contraction of words it's made up of. Would have.

Re: BusKill: A kill cord for your laptop

#13

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.

Shared medium (i.e. wireless spectrum) means anybody can do that, without being too conspicuous. A wire is significantly harder to DoS ;)

(Plus I tried several solutions to do this; BT is not really well suited for proximity detection, teeming with false positives and false negatives)

Re: BusKill: A kill cord for your laptop

#14
post #5
post #3

Earlier quoted context omitted.

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")

Other English speakers I know complain about our orthography: bought, caught, draught, etc. But, yet, here we are with a “word” pronounced “of” and spelled “‘ve”! Now that’s awful orthography!

The word should be pronounced the way the contraction actually is would (ha)ve.

But people are lazy. And words like caramel get blurred over. Or the one that bugs me the most of saying ‘ta’ instead of to.

My favorite is the Futurama universe where the word ask is official changed to ax instead.

Re: BusKill: A kill cord for your laptop

#15

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?

> [...] rule that will trigger xscreensaver to lock the screen every time any USB drive is removed

Re: BusKill: A kill cord for your laptop

#16

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.

If you are doing proper OpSec, you would have whole disk encryption anyway, in which case destroying the computer is largely unnecessary, I think.

That said, the caveat of XKCD 538 (https://www.xkcd.com/538/) still applies.

Re: BusKill: A kill cord for your laptop

#17
Saw a demo 20 years ago at Infosec(UK) of a company selling a dongle which with corresponding pass, acted as a proximity authentication and locking when you walked away.

Today, most laptops have cameras which can offer the same level of proximity detection if you away from the laptop. That would make this type of solution doable via software that way, albeit a bit more of a software load overhead.

But for some killcord, I'd also have an alarm.

Re: BusKill: A kill cord for your laptop

#18

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 can do whatever you want it to do. The examples in the article were:

• whenever any USB drive is removed, trigger xscreensaver to lock the screen:

> ACTION=="remove", SUBSYSTEM=="usb", RUN+="DISPLAY=:0 xscreensaver-command -lock"

• whenever a specific USB drive is removed, shut down the computer:

> ACTION=="remove", SUBSYSTEM=="usb", ENV{ID_MODEL}=="Micromax_A74", RUN+="shutdown -h now"

Re: BusKill: A kill cord for your laptop

#20

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?

The article shows two different configurations, one that simply triggers the screensaver with a lock screen, the other to fully shut the machine down. Recovery from both of those is fairly straightforward.
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