Is there any way to protect computers from the USB vulnerabilities exploited by the likes of USB Killer and other similar attacks?
(Protection aside from a strict data protection compliance schemes and inspecting each USB you use like a hawk)
Cheers
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Pour concrete in your USB ports.– xvk3Aug 2, 2017 at 9:51
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There really isn't a good answer, because a good protection doesn't exist AFAIK. Since USB killer really isn't using a vulnerability, it simply stores electricity and pushes it back into the motherboard all at once... Other than disabling usb fully (which might not even protect you since some manufacturers don't stop power on the usb port even when disabled through bios) or using @WillV advice you can't really be protected (I think the USB killer producers sell a protection you plug in between the usb port and the killer but that is highly impractical, especially with how rare attacks are)– Ladislav LoukaAug 2, 2017 at 10:02
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Many thanks Ladislav Louka, I completely understand there wasn't a good answer for this query. I tried a terrible pun in my last comment, I admit. My question was more me wanting to know if there certainly was not a solution other than the good old concrete technique. Thanks both for your input– user68786Aug 2, 2017 at 10:56
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2 Answers
Make a little box connected to a 5V switching mobile charger. Get some breakout USB ports. Connect the 5V rail to a LED across a 220 ohm resistor, and in parallel connect the 5V and GND rails to the USB port. If a USB killer is connected to this port, that LED will flicker. The charger will probably die, though I doubt it will begin burning. I expect you will hear a little pop as the capacitor in the 5V charger goes bye-bye. It shouldn't trip your breaker box, though. Cost: less than 5 USD.
If the LED stays on, nice and stable, you don't have any problem. The USB killer works very poetically by charging capacitors, then driving a negative ~100 volts against the positive 5 volts of the USB port, bypassing protection circuitry. Less would probably be enough to murder a motherboard, but its creator is from eastern europe. In any case, this negative voltage would disrupt the light of the LED, and so serve as an indicator of attempted vandalism.
Connections:
- 5V -> 220 ohms resistor -> anode of LED -> cathode of LED -> GND
- 5V -> 5V pin on USB port
- GND -> GND pin on USB port
Use a stripped USB cable, you only need the red and black wires.
On second thought, a properly rated schottky diode forward biased to the 5V pin of the USB, and one reverse biased to the USB GND pin might be useful in a PC/laptop setup. From looking at the page, it seems to present -200V DC to the 5V pin. I have a nice 0.18V schottky here, but only rated for 40V@1A. Most USB chargers and PSUs offer ~5.10V, and a nice schottky (>200V, Vdrop 0.1V) here can probably be used.
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Hi User2497 thanks for this, in retrospect this question probably should have been posted to the electronics stackexchange. Can I just ask (don't worry if you don't know off the top of your head, I can go and research) are such USB killers one use or multiple use? I'm also mainly interested in thinking about why someone would want to use one of these devices, aside from making sure certain data is completely erased. Thanks! Aug 2, 2017 at 11:00
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@user68786 The lore is that when you find one, it has a number written on it. When it murders your PC, you increment that by 1, and leave it for someone else. They're cool things to let people steal (I've had a few thumbdrives stolen), and infosec.SE is an ok forum for this. This device gives many IT nerds both the shivers and the giggles. Yes, USB killers can be used multiple times. It's an array of SMD capacitors wired up funny, with some extra kung-fu to trigger the discharge. Try finding the schematic on google images.– user2497Aug 2, 2017 at 11:04
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Ha-ha, I would like to believe such a mysterious lore is true. I will take a look on Google images at the schematic of the electronics inside. I imagine whoever steals the USB wont be too happy when they plug it in. I suppose that's instant Karma. Thanks for your answers! Aug 2, 2017 at 11:24
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Here on stackexchange, upvotes and accepting answers is the custom 👍– user2497Aug 2, 2017 at 11:40
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Finally found the tick I was looking for! (Its slightly different to the SharePoint stack exchange I have used before!). Thanks for your time and answers :) Aug 2, 2017 at 11:55
There's a product made for this purpose by the creators of the USB killer, USB Killer Shield/USB Killer Tester. It's available here: https://www.usbkill.com/usb-killer/9-usb-killer-tester.html
