Vid An internet mischief maker has built a USB stick that delivers dangerous 220-volt shocks to PCs, destroying them in the process.

The USB Killer is the second iteration of a laptop-wrecking device crafted by a Linux and infosec techie nicknamed Dark Purple. The first version of the PC-zapping hardware emerged in March, and pumped 110 volts of anarchic fun across motherboards.

"The device performs only one function: the destruction of computers," the Purple one wrote in a Russian-language blog post this month.

"But let's not limit it to computers. The device is able to incapacitate almost any equipment with a USB host interface. The main feature of the new version of the device is the doubled output voltage, which is 220 volts (strictly speaking, minus 220)."

The USB zapper looks like any conventional USB stick.

The Russian tinkerer says it uses a voltage converter that charges capacitors to 220V when plugged into a machine, drawing the power needed to do this from its victim. The stored energy is sent back through the USB interface, and the process is repeated until the computer drops dead.

It's a more sophisticated Etherkiller, but for USB.

The booby-trapped USB could fry smartphones that support USB OTG mode, plus TVs, routers, and other equipment, Purple says. If the circuitry is not designed to take a large amount of juice, it will fail. Typically, USB interfaces deal with five volts and up to 500mA for USB 2.0 and 900mA for USB 3.0 in current.

Youtube video demonstrating the USB killer stick

Security researchers have shown that employees will pick up mysterious USBs they find in parking lots and offices and plug them into their work computers. Doing so with one of these high-voltage charging sticks will send sparks flying across the office, perhaps literally. ®