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Of Boot Vectors and Double Glitches: Bypassing RP2350's Secure Boot

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Re: Of Boot Vectors and Double Glitches: Bypassing RP2350's Secure Boot

#21

Post by avidiax »

lll-o-lll wrote: post #9

What an interesting talk, and an interesting concept also. Open source hardware security; get the security researchers interested and fix the security defects. The “read the data out with a super expensive microscope” remained. Is there any way to defeat that attack I wonder? I suppose the hsm model of “destructive tamper detection” is one way.

You can also bury the fuse array inside the chip. So in addition to the microscope, you will also have to non-destructively etch or mill the chip to expose the fuses. This also renders the chip non-functional, so if the secret is unique per chip, then the leaked secret can't be used to bootstrap to other secrets on the die.

Re: Of Boot Vectors and Double Glitches: Bypassing RP2350's Secure Boot

#22

Post by avidiax »

lysace wrote: post #20

I've had a bit of a difficulty of understanding the actual benefits of proper secure boot vs zero protection. I've arrived at this understanding: secure boot sometimes allows you to recover a compromised fleet without recalls. Instruct the customer to disconnect the device, reboot it and then somehow reflash it before getting infected again? Seems fraught with errors though. When I worked with IoT HW companies in Tai…

It also prevents "contempt of business model". Makes a SW or HW bypass for ink cartridge pairing or game piracy or monthly widget subscription difficult or impossible. May also make any vulnerability patchable.

If you depend on your firmware remaining secret, however, you have to contend with the black hat version of the presenters. They are expert at extracting firmware and cloning. Some applications choose FPGAs in part because the equivalent of their firmware (the bitstream) is itself nearly impossible to reverse engineer. That means that a one-for-one clone is possible, but you can't alter the design, and have to use the exact same part.

Re: Of Boot Vectors and Double Glitches: Bypassing RP2350's Secure Boot

#23

Post by Thorrez »

compsciphd wrote: post #15
londons_explore wrote: post #7

Real security processors never give big bounties because when bugs are discovered all the buyers immediately cancel their orders of the 'faulty' secure chips. They'd prefer to live in ignorance.

really big bounties would then be appropriate, as they would come with NDAs. Small bounties would just encourage others to make them public / sell them to more malicious actors.

What if multiple people discover the same vulnerability. What do you do?

Do you pay out to all of them? Do you make them sign an NDA without guaranteeing you'll pay them? Do you tell the 2nd etc discoverers to go away and hope they don't reveal it?

If you pay out to all of them, there's a strong incentive to leak info and collect multiple bounties for the same vulnerability.

Re: Of Boot Vectors and Double Glitches: Bypassing RP2350's Secure Boot

#24

Post by londons_explore »

Thorrez wrote: post #23
compsciphd wrote: post #15

Earlier quoted context omitted.

really big bounties would then be appropriate, as they would come with NDAs. Small bounties would just encourage others to make them public / sell them to more malicious actors.

What if multiple people discover the same vulnerability. What do you do? Do you pay out to all of them? Do you make them sign an NDA without guaranteeing you'll pay them? Do you tell the 2nd etc discoverers to go away and hope they don't reveal it? If you pay out to all of them, there's a strong incentive to leak info and collect multiple bounties for the same vulnerability.

You hire a salaried security researcher and forget the idea of bounties.

Re: Of Boot Vectors and Double Glitches: Bypassing RP2350's Secure Boot

#25

Post by rcxdude »

michaelt wrote: post #13
lll-o-lll wrote: post #9

What an interesting talk, and an interesting concept also. Open source hardware security; get the security researchers interested and fix the security defects. The “read the data out with a super expensive microscope” remained. Is there any way to defeat that attack I wonder? I suppose the hsm model of “destructive tamper detection” is one way.

> The “read the data out with a super expensive microscope” remained. Is there any way to defeat that attack I wonder? Get your chip made with the latest TSMC process and get features so small nobody else, even superpowers and trillion-dollar tech companies working together, can manipulate them :)

Manipulating features smaller than what TSMC manufacture is possible in many places (just at great expense), TSMC's special sauce is being able to manufacture it in quantity and economically. Ultimately it's always going to be difficult to completely protect storage at rest, because it is possible to take something apart atom by atom, but it does raise the cost of the attack substantially.
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