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The USB Kill Stick, Priced at $56, Is Designed To Destroy Laptops, PCs, TVs (zdnet.com)
There's a new USB Kill device in the market today which can destroy any device it touches. ZDNet reports: For just a few bucks, you can pick up a USB stick that destroys almost anything that it's plugged into. Laptops, PCs, televisions, photo booths -- you name it. Once a proof-of-concept, the pocket-sized USB stick now fits in any security tester's repertoire of tools and hacks, says the Hong Kong-based company that developed it. It works like this: when the USB Kill stick is plugged in, it rapidly charges its capacitors from the USB power supply, and then discharges -- all in a matter of seconds. On unprotected equipment, the device's makers say it will "instantly and permanently disable unprotected hardware." You might be forgiven for thinking, "Well, why exactly?" The lesson here is simple enough. If a device has an exposed USB port -- such as a copy machine or even an airline entertainment system -- it can be used and abused, not just by a hacker or malicious actor, but also electrical attacks.
Didn't see the You-tube video of the concept version of this being demoed on a laptop did you? Fried the screen and board in the first pulse and took out the power system and everything else with the second (each pulse takes about a second to charge and release). These things are not pushing a 10V signal on a 5V line, they are pumping a 230V charge into the port with magnitudes more amperage than static electricity, the simple over-voltage protections on current USB ports can't protect against this.
A real solution to a device like this will require a far more robust design on the over-volt protection on the ports. Something that can resist 200V+.
The Ethernet Killer is probably worth mentioning, too.
"First they came for the slanderers and i said nothing."
As an EE, I have some experience with this. I really do digital logic chip design, and leave the design of the IO pins to the analog guys (and I am NOT an analog guy)...
However, pins are designed to dissipate excess charge using the "human body model." The specification is charging a small capacitor to a few thousand volts and dissipating that into a pin. Since the capacitance is small, the total amperage is very small. There are zener diodes built into IO pads that can handle this small amount of current. An ESD event will only last for the barest fraction of a second. Now, if you actually intentionally put too much voltage across pins for a prolonged period of time, I can easily imagine those zener diodes dying. Once that happens, the voltage will start to play merry hell with the logic.
I also did some government (military) work a decade ago. With those systems, you generally hardened them against EMP pulses (don't want a nuke taking down your electronics), so we used something called "transorbs.". Basically, these are big, beefy external zener diodes that can clamp this type of event. HOWEVER, from what I recall, those diodes put too much capacitance on the line, which would do very bad things to high-speed data lines, such as the ones found in USB data lines. Transorbs are great for things like low-speed serial port lines (which explains standards like MIL-STD-1553. I do not know if transorbs have improved much (not done that sort of thing for 10 years), but these are the types of problems you have to face when dealing with something like this -- the devices needed to protect your USB ports might just make your USB ports unusable.
"-1 Troll" is the apparently the same as "-1 I disagree with you."