Faith may be a marvelous foundation for many things, but it's a terrible basis for cybersecurity. Andrew "Bunnie" Huang, founder of Bunnie Studios, says that evidence, not faith, should be the foundation on which security is built. "What we're not looking to rely upon is faith-based trust, as in ... I believe that this vendor has a great brand and therefore I will take their word at face value," he says.
The problem with a move to evidence-based security is that it's so difficult to rigorously inspect what is going on inside any given chip or system. And without such an inspection, a customer has to trust not just a vendor but the vendor's entire supply chain. "I want to be able to confirm that there are no extra parts in a motherboard," Huang says as he begins to describe a system he calls Precursor, which would allow people to compare what the motherboard looks like versus a published reference of that same motherboard.
Huang says that it's important to understand the problem that Precursor is designed to solve. First, the system is designed to give insight into system hardware, not software. It does that with its own hardware based on a field-programmable gate array (FPGA) that will be programmed with the model of what the reviewed system is supposed to be. That model includes details down to the transistor and logic gate level on the tested system.
Attackers, especially sophisticated nation-state operators, may be able to build in or take advantage of backdoors that leave no trace, Huang says, but Precursor requires the software required to take advantage of a vulnerability to be much more complex. Instead of adding circuitry that might take advantage of a single counter, Huang says, a successful attacker might have to use techniques that took every counter into account on the hopes that one would "sneak through" the inspection process. That makes the hardware required much larger physically and much more complex.
Huang isn't under the illusion that this will be a complete solution to the problem of hardware-based attacks, but it does restore some balance to the battle, he says. "The problem is that in hardware, we didn't even have the cat and mouse game. In hardware, you've got something and you either believed it was what you got or you didn't," he explains. Now, the hardware attackers will have to work around the knowledge that their exploits can be discovered and exposed.
The FPGA-based system also will have the ability to push hardware patches to vulnerable hardware, Huang says. That can significantly reduce the cost of remediating vulnerabilities in hardware because entire systems might not have to be replaced in order to close the vulnerabilities.
Huang will discuss Precursor and its genesis in the concept of evidence-based trust in the keynote address for Black Hat Europe 2020. The address is scheduled for 9 a.m. to 10 a.m. GMT on Thursday, Dec. 10.