Overcoming the potential downside of TCPA

[Joseph Ashwood]

----- Original Message -----
From: "Ben Laurie" <ben at algroup.co.uk>
> Joseph Ashwood wrote:
> > There is nothing stopping a virtualized version being created.

> What prevents this from being useful is the lack of an appropriate
> certificate for the private key in the TPM.

Actually that does nothing to stop it. Because of the construction of TCPA,
the private keys are registered _after_ the owner receives the computer,
this is the window of opportunity against that as well. The worst case for
cost of this is to purchase an additional motherboard (IIRC Fry's has them
as low as $50), giving the ability to present a purchase. The
virtual-private key is then created, and registered using the credentials
borrowed from the second motherboard. Since TCPA doesn't allow for direct
remote queries against the hardware, the virtual system will actually have
first shot at the incoming data. That's the worst case. The expected case;
you pay a small registration fee claiming that you "accidentally" wiped your
TCPA. The best case, you claim you "accidentally" wiped your TCPA, they
charge you nothing to remove the record of your old TCPA, and replace it
with your new (virtualized) TCPA. So at worst this will cost $50. Once
you've got a virtual setup, that virtual setup (with all its associated
purchased rights) can be replicated across an unlimited number of computers.

The important part for this, is that TCPA has no key until it has an owner,
and the owner can wipe the TCPA at any time. From what I can tell this was
designed for resale of components, but is perfectly suitable as a point of
attack.
                    Joe


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