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Protection against Killer USB Thumb drives

Joe Howard
Intellectual 2970 points

I recently read some articles about some USB devices that are specifically designed to destroy hardware.

"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."

Do we have any devices or ideas on how someone can design a USB port that could defend against such a device and prevent hardware damage?

Cheers,

Joe Howard

  • 0
    Guru 244230 points

    This is much more energy than any existing ESD circuit is designed for. And to divert the current from the signal lines into the power supply wouldn't be a good idea either.

    I guess it would be possible to create an active ESD protection circuit that can handle this specific case and dumps everything into a sufficiently large capacitor, but nobody would want to pay for it.

    And in any case, a USB stick that works but contains interesting software could do even more damage. If you want to protect against users that might connect unauthorized devices, you have to cover all USB ports.

    And this is not USB specific; any external connector can be abused like this.