Custom USB Drive Designed to Destroy a Computer
Ashley Allen / 2 years ago
If you’re in the habit of picking up random USB flash drives and plugging them into your computer, now would be a good time to stop. The mischievous Dark Purple has built a custom USB drive designed to fry any computer that it is plugged into.
From Dark Purple’s blog:
The basic idea of the USB drive is quite simple. When we connect it up to the USB port, an inverting DC/DC converter runs and charges capacitors to -110V. When the voltage is reached, the DC/DC is switched off. At the same time, the filed transistor opens. It is used to apply the -110V to signal lines of the USB interface. When the voltage on capacitors increases to -7V, the transistor closes and the DC/DC starts. The loop runs till everything possible is broken down. Those familiar with the electronics have already guessed why we use negative voltage here. I‘ll explain to others that negative voltage is easier to commutate, as we need the N-channel field resistor, which, unlike the P-channel one, can have larger current for the same dimensions.
In other words, the flash drive draws power from the system. When the power stored hits a certain threshold, it fires it back into the computer, sending an electronic surge across the motherboard and processor, frying any components it comes into contact with.
Thankfully, Dark Purple has not released schematics for the “USB Killer”, but it should still make you think twice next time you want to check out an unfamiliar flash drive.