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BusKill: A kill cord for your laptop

tech.michaelaltfield.net

131–140 of 272 posts

Re: BusKill: A kill cord for your laptop

#131
post #95

echo o > /proc/sysrq-trigger (read linux/Documentation/admin-guide/sysrq.rst before you try this)

shutdown -h now or the more recent incantation (from memory) systemctl shutdown would be less violent. AFAIK it can't be stopped either, and at least it sync's and umount's filesystems properly.

Violent is the point-- shutdown might be prohibitively slow. Or it'll get stuck waiting to umount a network share. Or maybe, you want the DRAMs to go dark and start losing ASAP, I don't know. If you must, simply precede 'o' with some sequence of 's', 'e', 'u' so it'll go down hard and fast, but still a bit controlled. I find that 'u' succeeds more often if done after 'e'.

FWIW, this is just what I do with the keyboard (but more slowly) when something went wrong enough that I can't even switch to a text VT and recover. Sometimes even 'b' won't hard reset it-- which indicates everything was already hosed, or maybe just the keyboard. Presumably the umount didn't work either, but I gave it a chance.

Re: BusKill: A kill cord for your laptop

#134
post #108

A man just died in Oakland today trying to recover his laptop that was snatched from him in a Starbucks. http://nypost.com/2020/01/02/man-dies-after-trying-to-stop-t... Definitely don't go running after your stolen laptop, let it go.

I'd definitely give chase. To me, it is worth dying for. Not because of the laptop, but out of principle for vigorously fighting these ridiculous crimes. We all need to collectively fight back against crime or it will be normal (as it is now).

Oakland's a bit of a special place. I have friends living there who have been robbed at gun point, for example, and if you go into a Subway the workers are often behind bulletproof glass because they've been held up so often. Chasing a crook in Oakland is just going to get you dead, not change anything there. Not smart.

Re: BusKill: A kill cord for your laptop

#135
post #16

Earlier quoted context omitted.

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.

Are there any known cases of western police forces beating people with wrenches until they gave up passwords?

I think waterboarding is more common. For US citizens they're usually stuck with just solitary confinement, which is a working form of torture but is kind of slow.

Re: BusKill: A kill cord for your laptop

#136
post #86

Earlier quoted context omitted.

> This is a really neat project but it’s also not really a solution to anything. Knowing your encrypted data is inaccessible to a thief is a huge relief, and may have saved this man's life: A man working at Starbucks had his laptop stolen. He was killed when he chased down the thief. https://www.cnn.com/2020/01/01/us/oakland-laptop-thief-starb...

Some faith in the Oakland PD to actually work property theft cases might have saved his life

In my experience with the priorities of police departments in general, this faith would be misplaced.

Not that a laptop or data is worth your life (usually).

Re: BusKill: A kill cord for your laptop

#137
post #33

Earlier quoted context omitted.

I suppose if the drive is encrypted and requires a passphrase at boot, it's effective for FBI raids, etc.

Whenever I read stuff like this I am forced to wonder just what the fuck people are doing that they feel such a pressing need to hide their data from law enforcement. I mean, I have plenty of things to hide just like any other reasonably interesting person, but none of it is outright criminal.

They could be organizing protests in Hong Kong. Or be a union organizer in South Africa.

Re: BusKill: A kill cord for your laptop

#138
post #102
post #69

Earlier quoted context omitted.

I remember watching a Defcon conference where they tested different methods for destroying a hard drive in place. And they found that thermite actually doesn't damage the platters (well at least not enough for data to be unrecoverable). Hard drive platters are surprisingly heat/chemical resistant. I think they found that the best method was to physically destroy the platters.

I remember watching that talk years ago. I was disappointed in the lack of rigor of their conclusions. The whole point of thermite-based HDD destruction is to get the platens over the Curie temperature so the magnetic field is gone, not to physically destroy them. They point this out in the start, but then never talk about whether this was achieved or not in their experiment (assumably so they could go on to the actu…

The guy worked on it further. He eventually solved the original challenge.

Re: BusKill: A kill cord for your laptop

#139
If you're using a macbook, isn't "Find my mac" enough to erase remotely?, I understand this is a faster disabling mechanism but also a bit inconvenient. I wish there was something even easier, like a tiny usb drive with a remote control
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