A Habrahabr user writing under the pseudonym Dark_Purple claims to have designed and created a flash drive capable of destroying a computer, when inserted into its USB port.
Dark_Purple got the idea for the USB stick after misreading a story on the website Bash.im, where a man claimed to have stolen a memory board that wrecked his computer’s motherboard, when he tried to install it. Dark_Purple thought the story was about a flash drive, not a memory board, and he wondered if it was possible to create such a device.
After designing a prototype in about a week, he ordered a new USB circuit board and installed his “armed” version of the device. The finished product is the same size as an ordinary flash drive, mounted inside a similar-looking case.
The device operates by emitting through USB voltage input channels enough electricity to overwhelm a computer’s voltage regulator, permanently “frying” its vital components. What Dark_Purple’s device burns out specifically differs from case to case, though he says he didn’t conduct extensive tests on different machines, for obvious reasons. “Whatever I could fry for tests, I fried successfully. But it would be a waste to wreck a bunch of working computers,” Dark_Purple explained.
The flash drive works simply enough. When you connect it to a USB port, it activates an inverting DC/DC converter and charges the capacitor to -110V. Then the DC/DC disconnects, simultaneously activating a field transistor, through which -110V flows directly to the USB interface signal lines. By increasing the voltage on the capacitors by as much as -7V, the transistor shuts down and restarts the cycle, until you’ve broken through everything.