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Does any USB host device provides any unique IDs which are available from USB controller to device? At software side, I can get the vendor ID (along with other hardware identification data such as BIOS and hard drive IDs), but looking for the way to implement a basic USB key-based protection by looking onto USB host data which is available from both software and hardware side.

In my particular case, I am interested in any fingerprint data that is leaked from standard USB host controllers found in nowadays PCs: BIOS-extended data, PnP/non-PnP requests (for example, will a BIOS trying to negotiate with USB flash key send any host IDs?), a presence signs of other presumably internal USB devices like laptop cardreaders which sit on the same bus, etc.

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  • \$\begingroup\$ I'm having some trouble understanding your question. Correct me if this is wrong: From the perspective of a USB device, you want to be able to uniquely identify the host it is attached to for some kind of access/privilege control? And this identification information must be available by 1) query at the host's application level and 2) through the USB bus by passive "observation" by an attached device? \$\endgroup\$
    – Jon L
    Nov 25, 2011 at 21:39

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There is nothing in the USB spec that forces a host to identify itself, and there is no standard way a device can request such information. Without a cooperating driver in the operating system, there is no way for a ordinary device to know details about the host, like what operating system it is running, what processor it is using, etc.

I have, however, noticed that different operating systems tend to have their own quirks about what they request in what order during enumeration. You might be able to do some testing and find a way to distinguish a few of the major operating systems. However, that would not be guaranteed, could easily change at minor revisions, and can certainly be deliberately spoofed.

If you want a device to know it is connected to a trusted host, you will have to previously load software on that host. The device could, for example, send out a randomly generated string of bits when asked the right way by your software on the host. The host must then respond with a reply that is hashed from the original bits in a particular way envolving a password. Only a host with the right algorithm and password could reply correctly.

Of course that is just simple scheme. It can get a lot more complicated depending on what level of attacker you want to protect youself from. For example, the simple scheme I described above would be no good against a man in the middle attack.

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  • \$\begingroup\$ I want to know that a device which is connected to my host has no chance to remember its parameters by just identifying itself to the controller (without any help from software side). Going to examine that with an USB sniffer/analyzer anyway. \$\endgroup\$
    – kagali-san
    Nov 26, 2011 at 16:22
  • \$\begingroup\$ FYI, this kind of algorithms for establishing trusted communication is known as challenge–response authentication. \$\endgroup\$
    – Dmitry Grigoryev
    May 28, 2018 at 10:58
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It's not as simple as getting a unique ID, but one way to do it is discussed in the following paper:

Host Identification via USB Fingerprinting (now broken url)
Archive.org mirror of 'Host Identification via USB Fingerprinting'

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