J.A. Terranson wrote:
Also, that Cisco must fix was not the point of my argument. I was trying to point out that Jason's basic premise that this was a grossly negligent act by Cisco is pure fiction.
Not at all -- you're simply constraining the discussion to all known CPUs and I'm referring to the duty that a company like Cisco obviously has to make a better mousetrap if they intend to sell it to millions of people and coax billions of people to rely on the devices.
There are any number of technical solutions that one could use to redesign, fundamentally, the turing machine so that before each operation is performed a verification step is employed to ensure that the operation is the correct one in the correct sequence given prior configuration settings loaded into memory at the time the device was activated.
Store the necessary security profile, which could very well be just another copy of the entire machine code, in a separate memory that can be accessed in parallel and used solely to verify that the operation about to be performed matches the operation that is supposed to be performed. Require a physical act by the owner of the device to populate the security profile data storage so that it cannot be automated through the execution of code, and you enable both the software reprogrammability of the computing device and the non-programmability feature that provides the proper security safeguard.
This is a very high-level explanation, to be sure, but there's no reason not to redesign the CPU if you're Cisco. Or if you're Microsoft, or Intel, or AMD, for that matter.
CPUs are unnecessarily-insecure by design, as a result of people running around saying that you just can't change the way that a turing machine operates. That's what's pure fiction. Turing machines don't need to be allowed to operate in a vacuum, they can be sanity-checked at runtime if anyone cares to do so.
I am not suggesting that such CPUs exist today, only that they should and that a company like Cisco knows this very well and chooses not to undertake this engineering challenge, presumably because it would cut into profits.
Regards, Jason Coombs [EMAIL PROTECTED] _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
