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Secure Boot is broken on 200 models from 5 big device makers

arstechnica.com

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Re: Secure Boot is broken on 200 models from 5 big device makers

#51

Post by acdha »

out-of-ideas wrote: post #43
acdha wrote: post #22

Earlier quoted context omitted.

Also things around physical access: if you steal my laptop, FDE prevents you from getting my data immediately but if you install malware which takes over the boot process, you get that data as soon as I type in my password. If the process changes so the hardware only loads signed firmware, which only loads a signed boot loader, which only loads a signed kernel, etc. that avenue of attack is closed. It also makes it p…

do folks in the business really simply steal a laptop and try to pull all data? or do they steal the laptop and wipe it and flip it... if they wanted your data wouldnt they steal you, the human, too ? the signing method only offers buying more time before the innevitable data is "breached" by a theat actor - its the same buying-time for any and all encryption. the system can get too complex, and the underlying proble…

> do folks in the business really simply steal a laptop and try to pull all data? or do they steal the laptop and wipe it and flip it... if they wanted your data wouldnt they steal you, the human, too ?

Governments definitely worry about it, and I’d be shocked if e.g. banks didn’t also put it into requirements. Access can be temporary, too: imagine if you get 15 minute alone in someone’s office or they have a kiosk in the lobby, etc. – not enough time to open the case up but plenty to toss a USB drive in and reboot. Repeat for lost devices or scenarios like the KnowBe4 attack disclosed yesterday where some dude might not be able to explain cracking the case open.

> the signing method only offers buying more time before the innevitable data is "breached" by a theat actor - its the same buying-time for any and all encryption.

You have to think about cost, too. It appears to be safe to buy a used Mac because Apple employs competent cryptographic engineers and very few targets are worth involving a lab with truly serious hardware. This could be the case on the PC side too, but it’s undercut by vendors skimping on execution and until Secure Boot is pervasive and robust, nobody can easily tell whether hardware they’ve lost control of can be trusted. People have been getting malware on used computers for years and a trusted boot process makes it easier both to tell if that’s happened and to be confident that you’ve fully wiped a system.

Re: Secure Boot is broken on 200 models from 5 big device makers

#52

Post by sillywalk »

jauntywundrkind wrote: post #5

It feels utterly absurd that devices typically have certain keys are baked in, cannot be removed. I believe there are still Microsoft keys on nearly every device? It's unconscionable to tell users this is here to keep you safe, but that you have no control over it & if something goes wrong well then too bad, at best we might provide an update. (Also that governments can probably force these root-of-trust companies to…

As I understand it, that's both the whole point of, and limitation to, the hardware root of trust - it can't be changed even with a firmware update.

Of course, if the key used to sign the firmware is compromised, the root of trust is still technically what it is supposed to do - verifying signatures, it's just that that it becomes irrelevant in terms of security / integrity.

Re: Secure Boot is broken on 200 models from 5 big device makers

#53

Post by Scoundreller »

upwardbound wrote: post #48
schmidtleonard wrote: post #46

Earlier quoted context omitted.

Writing flash takes (relatively) high voltage and the voltage boosting circuitry could be routed through a switch. It generally isn't, and the voltage converter is often an on-chip charge pump so this wouldn't be an easy retrofit, but the current state of affairs is due entirely to lack of interest rather than lack of possibility.

Do those charge pumps use external capacitors? If so, you could disconnect/float those capacitors, or if that would damage or glitch the chip, you could replace the real capacitors with some circuit like a voltage regulator + diode that would be designed to provide the charge pump output rail with a voltage that's high enough not to glitch the chip but low enough to be unsuccessful in writing to the flash. Would one…

I believe they’re on-die capacitors for the charge pumps these days. The external ones are just for smoothening.

Probably a method to retrofit write/erase protection would be to just do power analysis and cap the current the flash chip can receive. Or shut it down if that works for you.

Not sure if they’re intelligent enough to run their charge pumps slower under compromised electrical conditions. Or if they’ll go haywire if they can’t do idle-time wear levelling/block erases.

Re: Secure Boot is broken on 200 models from 5 big device makers

#54

Post by bluescrn »

tedunangst wrote: post #29
drhagen wrote: post #6

> To this day, key players in security—among them Microsoft and the US National Security Agency—regard Secure Boot as an important, if not essential, foundation of trust in securing devices in some of the most critical environments, including in industrial control and enterprise networks. Am I correct that Secure Boot purely exists to prevent this attack vector: malware gets root on the OS, hardware allows updating f…

How do you determine when to push the button?

Instead, write-protect the firmware by default, and require the user to press a physical button on the back of the PC to write-enable it (for a limited duration/until the next reboot)

Re: Secure Boot is broken on 200 models from 5 big device makers

#55

Post by leeter »

jandrese wrote: post #18
hex4def6 wrote: post #10

Earlier quoted context omitted.

This has been my theory since Windows 11 required TPM. It's not to protect the consumer, it's to protect the IP-holder. The PC is the lone outlier in the locked-down, walled-garden world of consoles, cell phones, tablets, smart TVs, EVs, etc. I think there's a concerted effort to change that.

Absolutely. Look at all of the changes to the media stack Microsoft made for Vista and none of them are to directly benefit the person who bought the OS license. If you have ever wondered how a 486 could play MP3s and still run X but your modern laptop gets hot and spins the fan when you are playing those same MP3s it is because the media companies demanded it.

The pedant in me wants to point out that most 486s couldn't play MP3s (they just don't have the horsepower, an AM-586 or a DX4 maybe) and you'd need a Pentium. /pedant

OK now to my real point. Vista is actually a really good call out of MS being inconsistent about this. The major changes in Vista (Moving graphics drivers largely out of the kernel, simplifying what sound drivers could do) were all predicated on the fact that hardware vendors are notoriously bad at software. This cannot be understated just how bad they are, NTKernel was originally intended such that vendors would make their own HAL.. one tried and it was so bad MS just NOPE.jpg'd that and did it themselves. So for MS to double down on a system that relies on the same known to be horrible at software vendors is just hilarious to me.

Re: Secure Boot is broken on 200 models from 5 big device makers

#56

Post by jmclnx »

tedunangst wrote: post #26
jmclnx wrote: post #4

>In 2012, an industry-wide coalition of hardware and software makers adopted Secure Boot to protect against a long-looming security threat This joke never gets stale, wait it is not a joke ? I still believe the only reason for this to exist is to eventually turn general computing devices into a locked down Cell Phone Spying Device.

It's only a F12, tab, enter, down, tab, enter away to disable if you really don't like it that much.

Yes right now, what about 5 to 10 years from now ?

Or maybe for that option in the future, the device will cost thousands of USD more.

Or you need a special professional license to get a non-locked down device, and the license will cost more than a house in a rich suburb.

Re: Secure Boot is broken on 200 models from 5 big device makers

#57

Post by Scoundreller »

schmidtleonard wrote: post #46
Gormo wrote: post #35

Earlier quoted context omitted.

I can't imagine how it would be possible to do it any other way for a flash storage device. A mechanical hard drive could at least theoretically have a physical lock attached to the drive head which prevents it from approaching the platters if it is engaged.

Writing flash takes (relatively) high voltage and the voltage boosting circuitry could be routed through a switch. It generally isn't, and the voltage converter is often an on-chip charge pump so this wouldn't be an easy retrofit, but the current state of affairs is due entirely to lack of interest rather than lack of possibility.

Isn’t it really only the erase that requires high voltage? So with a blank flash chip, without higher voltages, you could write to it to your heart’s content until you need to free up deleted content?

Edit: I think I’m wrong here and high voltage is needed for both.

Re: Secure Boot is broken on 200 models from 5 big device makers

#58

Post by StillBored »

manofmanysmiles wrote: post #42

Unless I'm missing something, Secure Boot as designed is fundamentally broken. Its root of trust is the BIOS/Firmware, which can be updated from a running OS. There is no hardware root of trust. How Secure Boot Works Secure Boot ensures that a device boots using only software trusted by the Original Equipment Manufacturer (OEM). Here's a high-level overview: 1. Power On and Initialization : The CPU initializes and ru…

The firmware updates from a protected capsule so it can't be updated without a signature verification effectively closing the loop. Its possible to add a 3rd party root of trust (TPM/etc) to this, its just vendor defined whether a platform uses an additional component to validate the PK/firmware/etc earlier in the process.

Re: Secure Boot is broken on 200 models from 5 big device makers

#59

Post by commercialnix »

Hizonner wrote: post #31
drhagen wrote: post #12

Earlier quoted context omitted.

I remember USB drives in the '00s that had a read-only toggle. They were useful for rescuing machines that had a virus. Edit: A quick search reveals that, of course, you can still buy them today. I have not felt a need for one in ages.

I strongly suspect that most or all of the modern "hardware" write-protect switches are actually just suggestions to the drive firmware. Which may very well itself be modifiable.

This is the way a smart person looks at write-protect switches.

Re: Secure Boot is broken on 200 models from 5 big device makers

#60

Post by sillywalk »

acdha wrote: post #22
drhagen wrote: post #6

> To this day, key players in security—among them Microsoft and the US National Security Agency—regard Secure Boot as an important, if not essential, foundation of trust in securing devices in some of the most critical environments, including in industrial control and enterprise networks. Am I correct that Secure Boot purely exists to prevent this attack vector: malware gets root on the OS, hardware allows updating f…

Also things around physical access: if you steal my laptop, FDE prevents you from getting my data immediately but if you install malware which takes over the boot process, you get that data as soon as I type in my password. If the process changes so the hardware only loads signed firmware, which only loads a signed boot loader, which only loads a signed kernel, etc. that avenue of attack is closed. It also makes it p…

> other than Apple nobody has really been committed to doing it well

I believe Chromebooks also do this fairly well.

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