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Duh i take my phone out to the protest (sh.itjust.works)
submitted 1 year ago by to c/cybersecuritymemes@lemmy.world
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[–] 44 points 1 year ago (16 children)

Depends if the phone is supposed to still work.

If you just take an empty shell it shouldn't be hard at all to put an USB killer inside.

If you want to keep a functional phone, that's very difficult. You'd likely have to reduce the size of the battery by half to free some space and then design a custom USB killer to fit into that space. And then you need some kind of switch to switch between regular USB usage and USB killer mode. Or you just hard-wire it to USB killer only and charge your phone exclusively with wireless charging.

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  • [–] 10 points 1 year ago* (last edited 1 year ago) (1 child)

    Or you just hard-wire it to USB killer only and charge your phone exclusively with wireless charging.

    That feels really insightful.

    Saw this post earlier and was cranking some brain cycles in kinda the same way you were. My brain settled on a switch for the USB since you should just need a 5 pole/2 throw switch (think I'm using those terms correctly?) to go from regular USB function to kill mode. I think for my own peace of mind, I'd want it to be 3 throw though (normal, completely unconnected, and kill). My brain then went to the battery, which I see as the real design constraint.

    Then I got to thinking about building it into a phone case. The case would need to plug in to your phone's USB port, then have an additional external connection; it would be this connection that is switched into normal/nothing/kill mode. Cases can be pretty bulky, so tucking a battery into there would be easier and still maybe evade detection.

    All that said, I think I like your idea better.

    Edit: spelling

    Edit 2: additional thought: if you went with the case, you'd want to have it really difficult to remove. Like, requiring undoing some screws, especially if you can get some torx or other niche screw head design (bonus points for mix and matched screw heads).
    My thoughts on that are that even if the case is identified as having a false port on it, it would be so difficult to remove that the "adversary" just plugs their info stealer into it anyway.

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  • [–] 5 points 1 year ago

    The USB killer doesn't need a battery of its own. It charges capacitors from the USB supply voltage and then spikes a high-voltage discharge into the USB power pins. So you'd only need to change the battery to a smaller one to give you space for the USB killer. The battery is the only component on your phone that's reasonably easy to shrink while still retaining the phone's functionality (though obviously with reduced battery capacity).

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  • [–] 7 points 1 year ago (3 children)

    USB-C has a lot of pins, some custom built cable could use nonstandard pins for power and data and the standard data ones for the 20kV line.

    Or just run the 20kV line on the data pins and leave power standard. That way you can use a power-only cable to charge the phone.

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  • [–] 3 points 1 year ago (1 child)

    The pins are quite close to each other, wouldn't 20kV just jump between them?

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  • [–] 1 point 1 year ago

    True, didn't think of that.

    I guess a much lower voltage of let's say 200 volts would kill a device just as effectively and probably wouldn't arc itself.

    Another option would be a smart device that first senses some current and only then dumps the 20kV.

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  • [–] 7 points 1 year ago* (last edited 1 year ago) (9 children)

    You have piqued my curiosity. I was imagining a non-functioning device with the sole purpose of hampering USB/devices. Like if I were to, conduct research, I would probably just have the insides filled with sand or something to give it heft or the illusion of being a real phone.

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  • [–] 11 points 1 year ago (4 children)

    For a non-functioning one it's quite simple. There are dummy phones for most models that are to be used in e.g. store displays. You can get those for ~€5-10 on ebay. They are just a shell and nothing else. Alternatively you can just take an old phone and remove all the content, though the dummy will have more space inside, since you'll have to leave the screen in if you take an old phone.

    Then you need an USB killer. You can find them on the usual online shops. You'll need to find one that is as flat as possible, the other dimensions don't really matter.

    This is now the only somewhat tricky part: You will need to remove the USB port from the USB killer (unless it already comes with an USB C port), take an USB C socket (there are ones on a small breakout PCB), solder the socket to the killer and mount the socket inside the dummy/phone in a way that it sits at the right place and can easily be used without falling off.

    I would not use sand to make the phone heavy, as it's probably not that easily contained and it would also not be quite as easy to make it not flow around and sound like a salt shaker. Instead use fishing weights and glue them into the case.

    Now, don't forget, this is all hypothetical. Nobody's going to ever, ever build anything like that, and I wouldn't have ever told anyone how to do this if I thought that anyone would do it.

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  • [–] 13 points 1 year ago (3 children)

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  • [–] 6 points 1 year ago (2 children)

    Not hypothetical. For real world application. The police deserve it for illegally searching your phone.

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  • [–] 5 points 1 year ago (1 child)

    Honestly, just pack something with a USB port, and no descriptor. No labels, no nothing. Hell, make it out of a little hobby box container and put a port on it. Done.

    Some dumb ass will plug it in to see what it is.

    Remember, police have a maximum intelligence limit for hiring, or so its rumored, and if you've dealt with many cops, well.... seems pretty fair.

    Intelligent people ask questions. Fascism doesn't like people asking questions.

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