There is plenty of evidence that you should not let other people connect their USB devices to your computer. But I would really like to allow untrusted people to attach a USB-storage device to my laptop, and allow me to attach my USB-storage device to untrusted servers.
I have found a USB condom for safe charging that prevents syncing (by cutting the datalines), but what I am looking for is something that will allow USB-storage, but nothing else.
I can see how you could build such an adapter: Have a chip that understands the USB storage protocol. Only forward commands (and replies) that this chip understands. Include a fuse to prevent the USB-killer from frying your laptop.
Does such an adaptor exist?
Best Answer
Regarding the problem of allowing other people to attach their storage devices to your machine, it may be easier to simply separate your computer from the USB devices.
Why not use a minimal PC/Raspberry etc. with Linux to provide USB ports and share the storage contents over the wireless network. The number of attack vectors should be reduced and you can always check the processes running on this machine.
Alternatively just take an old WiFi router with USB-host functionality to avoid having to set up the Linux machine. The different architecture might even lower the probability that something is executed.
In both cases you will get rid of any USB killer problems and your PC will only see the USB storage.