Re: USB delivered attacks

From: Gadi Evron (ge@linuxbox.org)
Date: Fri Jun 04 2004 - 19:14:46 EDT


Rob Shein wrote:

> The driver for USB drives is not on the USB drive. It's native to XP/2000,
> and loads dynamically from the O/S.
>
> Look at it this way; if the driver were needed to access files on the USB
> drive, then how could the driver be stored on the device to be used to
> access files? If you could pull the driver off the USB drive, why would you
> need the driver at all?
>
> To further see what I mean, put in your USB drive and wait for it to
> connect. Then look in Device Manager, and check the driver details. Look
> and see whose driver it is. If you've got multiple drives from multiple
> companies, try them one at a time, and look to see if the driver changes.
> Bet you it doesn't. :)

I suppose you are right.

However, there is data on the USB drive itself.

The entry on the PC is the HUB. The USB device is the client. I can
think of a few ways the client can effect the HUB.

After re-examining the technology, I came up with the following
conclusions about possible threats:
1. Someone will put his/her own code inside a USB SDK, which will be
    catastrophic.
2. Some will find a buffer overflow in the Microsoft USB driver. That
    sounds quite plausible. It crashes under many circumstances.

A buffer overflow in the USB driver could possibly also effect very
strong cryptographic systems such as eToken, but as I didn't look into
that, I don't know if that particular technology is susceptible to such
an attack.

There is still the risk of somebody just copying stuff over, and that
can be expanded accordingly. I can put a file on my digital camera, say,
a .DOC file. Unless the memory card is removed and examined, I think I
can smuggle that file out pretty easily, even if my camera was to be
examined.

There is always the auto-run POC which did come out of all this, so I
suppose this thread wasn't a complete waste of bandwidth.

Thoughts?

        Gadi Evron.

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