Hello everybody,

I recently accuired an older ThinkPad and came across the TPM option in the BIOS, where you can disable the TPM chip and such.

I read up a little on TPM and came across this quote from http://thinkwiki.org/wiki/Embedded_Security_Subsystem which states:

Does this mean that a third party (software, a website, some remote 'attacker') can easily (?) gather identifying information from the TPM if they desire? For example, could a browser or operating system identify the unique (?) ID of my TPM module and therefore link it (and my computer) to visiting a certain website, even when the TPM is disabled in BIOS?

Wouldn't that mean that any hardware with TPM is automatically deanonymizable by default? I mean, of course, your computer is also identifyable by your IP or the MAC address of your network interface, but there are tools with which you can spoof those two. But can you spoof a TPM ID?

Even if such an identifying system isn't explicitly implemented by the manufacturer of the hardware, the existence of a unique identifier in your computer that cannot be spoofed and that can potentially be accessed in some way, would pose a huge privacy problem, right?

Sorry for the tinfoil but just wanted to be sure what that quote from ThinkWiki meant.

Greetings,
rokyo

The kernel code creates a set of entries in the /sys filesystem which provide general info on model, version and firmware rev that is readable by any user. Software running on your system, other than browser code which is restricted, could read this info. It would need root access to be able to operate the chip and do TPM key operations. JS code in your browser should not be able to read the contents of any file without your cooperation.

The point about being unspoofable is interesting. I can wipe my hard drive and nobody can tell I was the source of an SSH session, because the keys are gone. I can't easily get rid of the TPM chip. If it is used to identify a piece of hardware, then I'd have to incinerate the laptop to cover my tracks.

It would also be interesting if the TPM chip could be remotely activated, even when it was turned off by the user.

In the light of recent developments where Microsoft activated certain functions in Windows 10 with a Windows Update, even when the user had deactivated them before, I wouldn't be surprised if TPM could also be remotely activated... Microsoft does issue Windows Certified Hardware batches for PCs that have a TPM 2.0 installed, even when it is deactivated at shipping. Kinda makes me wonder if they could theoretically tamper with that chip remotely...

That's not quite true. I couldn't find the lost keys on your machine but the police could. When you wipe a disk (for example by overwriting it with zeros), the previous content doesn't disappear completely. Physically it's still there as a kind of ghost image. The police and counter-espionage bodies have ways of recovering that lost information.