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Comment by ChuckMcM | Hacker News Reader

Alternatively all USB-C thumbdrives become a threat once they hit the market.

Given your commend it USB-C specific, and the linked article mentioned USB-3 (which has a USB-2 connector variant) what is the mechanism on those ports for detecting a debugger?

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> Alternatively all USB-C thumbdrives become a threat once they hit the market.

All USB thumbdrives are already a threat. Not just from autoplay/execute, but there are malicious/pentester thumbdrives out there (like the Rubber Ducky) that emulate a USB HID keyboard; computers have absolute trust in keyboards, so you just have a script that instantly types in "Win-R cmd enter <download and run your exploit>".

There are also those fun thumb drives that will repeatedly bolt a couple Kilovolt into the USB port for shits and giggles.

Plugging in USB is just as unsafe as about anything else you can use a computer for.

How we ended up with an active device as our primary means of removable storage is me a puzzle...

Two Words.

Legacy Hardware.

We chose flash memory. It's a storage medium that involves a lot of tiny wires laid out in patterns going to the storage cell. We want to access these with only a few macroscopic wires connecting to a computer. This process has to be managed by a microprocessor of some sort.

Would you expect the host device to know the internal layout properties and hardware limitations of a purely passive bank of flash memory (e.g. when to mark a sector as failed)? It's possible but distributing the hardware and software to do this effectively would be a very difficult problem, and industry standardisation to mitigate it would be hard to arrive at as well, and deploying advances in flash memory would be hampered (remember when people worried about 720kb/1.44mb floppies? Imagine that for each new generation of flash memory. Is your flash drive slot MLC NAND flash capable? NOR flash? TLC? HKMG?)

Instead we live in a world where not just thumb drives, but even memory sticks and SD cards, are active devices. (This is, of course, to say nothing of the convenience of using one port for everything.)

facepalm

There ought to be some way to make a secure data transfer interface.

I guess not making it an universal bus is one of the steps for that. Also, making it either optical or magnetic should help.

SmartMedia and xD flash cards are notionally controller-less in the sense that the electrical interface is just parallel interface of NAND flash chip and all the FTL stuff is done by whatever device it's plugged into. one problem with that is that it requires all the devices to use same FTL logic with the standard one being NDA'd.

I don't think these threats are equivalent. You can detect a rubber ducky doing it's thing if you look at the screen, and the rubber ducky requires your pc to be unlocked, so you can easily defend against a rubber ducky by not leaving the PC unlocked.

With direct hardware access/DMA you can just plug a small device into, let's say a locked office cubicle computer and compromize/siphon data off it that way.

Considering the speed with which that attack can happen and that the macros can background the entire processing immediately (opens cmd, creates bat, executes bat, minimizes cmd), you only have to turn your back for a few seconds and an attacker can get into your system.

Imagine, you are sitting at your desk in the county clerk office and a citizen comes to see you about something. You turn your chair around for a few seconds to get a file and they insert the drive into the back of your computer and remove it before you turn back around. Do you honestly think that anyone beyond a security export or a spook would think they could be compromised that fast?

Looking at the video, Intel put in their own support for this on their standard USB-3 ports.[1] It's not USB-C hardware JTAG. It can be disabled in the BIOS settings, supposedly, and locked against further changes.[2] Apparently it ships enabled.

[1] https://youtu.be/QuuTLkZFsug?list=PLOcrXzpA0W82Z49Pj0v-cehuv... [2] https://youtu.be/QuuTLkZFsug?list=PLOcrXzpA0W82Z49Pj0v-cehuv...

Wow, time to find the special USB port and fill it with Epoxy on your system.

or put a solder bridge across the two pins.

I assume "USB Debug" option in my BIOS refers to this feature, however it did seem to be shipped "Disabled" for me.

I just looked into this on my Dell M3800 with A10 BIOS. This option derates your USB 3 ports to USB 2, so that older versions of Windows that don't support USB 3 out-of-box can still boot on the hardware. I assume once you get through the install from your USB stick, you would install drivers and disable this debug mode

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