5 ms·

I'm torn on this; on the one hand, the prospect of being able to circumvent things like unauthorized repair prevention down the line is neat, and who knows what

I'm torn on this; on the one hand, the prospect of being able to circumvent things like unauthorized repair prevention down the line is neat, and who knows what people may be able to tease out of this (apparently quite powerful chip). So that's neat. But it also breaks Apple's security platform in a big way, since this should make Apple's biometry scheme in their Macbooks much weaker and FileVault a lot easier to crack. That's a shame, because it's a very neat and cohesive security platform that gets out of one's way and works really well even for highly non-technical people. Their security stance is one of the things that keep me in Apple's ecosystem and I know a number of people and companies who feel alike. So, coming from that point of view, I do hope they fix this in time for their first round of ARM Macs.

saurik 6y ago
So, if only Apple didn't tie the ability to repair and extend the device you purchased from them to the security of your own data, you would be able to feel a more consistent emotion with regards to interest in a fix; that seems all on Apple being a bit evil :/.
- floatingatoll 6y ago
  Can you describe a scenario where Touch ID is safe against evil maid attacks (say, a chip is installed allowing anyone to transmit a certain signal that spoofs Touch ID) while also allowing unrestricted modifications by someone with physical possession of the device (as this T2 rooting post celebrates)? Right now, that security is provided by Apple crypto-locking the Touch ID sensor to the T2 chip so that it cannot be modified to allow unauthorized access without being disabled altogether. With the ability to bypass the restrictions of the T2 OS, that protection is stripped away, and replaced by .. nothing, as far as I can determine. This is akin to removing your car’s electronic anti-theft system because it requires OEM keys. Sure, you can do so, but your car is a lot easier to steal, too. Only it’s not your car here, it’s your computer and all personal data on it, and all SSH keys you use to access remote servers, too. I’m all for repairability but it’s worrying that the tech community is so invested in removing a padlock that offends them that they set aside security and risk issues in favor of rooting without addressing it at all. If this complete lack of interest in device security is the best we can do, we don’t deserve repairability, and we don’t deserve root.
  - the8472 6y ago
    Allow the users to install their own keys. Changing keys invalidates all encrypted/secured data. Which means you have to export the data if you do hardware changes and reimport it after supplying your own. Once you have your own keys installed you could sign additional hardware with them. If apple is a viable root of trust then you yourself should be too. There's nothing magical that only apple can do.
    - floatingatoll 6y ago
      I believe that Apple is burning their cryptographic key into readonly memory, so they would need to build out a readwrite pipeline and provide a secondary keystore option for "non-default" users that is writable by the hardware itself. That's a tall ask, but it's feasible, so we're good so far. The benefit to expert users with crypto competence is clear. How would this benefit third-party repair shops, though?
      - Nextgrid 6y ago
        The point is that you'd backup the keys in advance (when you initially set up the machine) and when the machine dies and your T2 is fried the repair shop can just replace it with a new T2, load the backed-up keys into it and give you back your machine with the data intact.
  - alexvoda 6y ago
    I do not understand why you find it worrying that the tech community is invested in removing a restriction IN THE OPEN. If it can be removed for nefarious purposes, eventually, someone will do so and sell the exploit on the zero-day market (probably to a state actor). The existence of the vulnerability is just a fact, it is reality. Why do you feel safer not knowing about it? Whether you know about it or not the vulnerability is still there.
    - floatingatoll 6y ago
      I do not ‘feel safer not knowing about it’. I feel safer knowing how to DFU a T2 Mac, though. It’s turning out to be very useful knowledge over time. I encourage you to learn how too.
- fastball 6y ago
  AFAIK, it's not just about the security of your data (you don't need a T2 chip to encrypt data), but also about discouraging theft of the hardware itself. In light of that, how do you allow for components to be swapped out wholesale without breaking the security model? Isn't the entire point that you can't just steal a Macbook, swap out the SSD, and now you have a functioning (stolen) laptop?
  - the8472 6y ago
    The initial transition from the apple root of trust to your own root (which you would then use to install new hardware) could require being authenticated, this way a thief couldn't do it while the legitimate owner could.
    - fastball 6y ago
      That's a route I hadn't thought of. Seems like a great idea!
  - dividedbyzero 6y ago
    You can also get away with a much weaker passphrase if you can somehow rate-limit brute force attacks. As I understand it that's one of the things the T2 does, you can't authenticate except through the T2, and the T2 will slow you down and lock you out after n tries. And I think that's actually incredibly underappreciated feature, most people are both bad at memorizing long, complex passwords/passphrases and not all that motivated since the threat is quite abstract. I've had a hard time convincing some people to have any sort of password at all on their laptop (that they travel with, work in all sorts of places and are overall pretty careless with), as it carries the risk of forgetting the password and it's cumbersome and inconvenient compared to being able to simply open the computer to a logged-in desktop. Making security less of a hassle really does help with adoption. Having a short, relatively weak, but not trivial password is way way better than having none at all, and realistically that's all most people are ever going to have, so making those passwords hold up better is a really smart move that instantly ups the security of lots and lots of people out there. But that's not something I believe you could do without a scheme like tieing the encrypted data to a complex secret inside a specific T2 that is uncracked, otherwise you could simply put the SSD in another computer and brute-force it there.
tinus_hn 6y ago
If it really matters, Apple can bring an update that blocks these attacks. If the system depends on security through obscurity, sorry, that never lasts.
- saagarjha 6y ago
  Apple cannot update this away; the vulnerability goes down to the very lowest levels of the software to the code burned into ROM.
  - selectodude 6y ago
    They were able to update it away on the iPhone X. Checkrain doesn’t work on iOS 14 anymore.
    - saagarjha 6y ago
      Well, somewhat. They’re doing a clever side channel based on the SEP’s RNG to panic the device when booting from DFU, but this has already been bypassed on older devices via a bug in SEPROM. I believe they already have code execution in the A11’s enclave as well, but that one has some sort of replay protection that complicates matters.
Benjamin_Dobell 6y ago
Apple did actually screw the pooch on this one. Typically, it's criminally illegal to circumvent DRM in the US (and 99% of the rest of the world). However, there are also certain exemptions that have been granted, within the US only (other countries are not so lucky). The right to repair is one such exemption[1]. If Apple had separated security from first-party repair enforcement, then anyone found even attempting to break the T2 chip might have been up for jail time. However, the right to repair is a valid defense. Of course, making circumvention criminally illegal doesn't make the chip itself any more technically secure; say against criminals. It is a pretty solid deterrent though. [1] https://www.copyright.gov/1201/2018/ https://www.copyright.gov/1201/2018/
- Daniel_sk 6y ago
  I bet breaking DRM is legal in most parts of the world. Good luck to any company trying to sue an individual for breaking DRM. "Article 6.4 of the European Directive mandates Member States to ensure users can benefit from the copyright exceptions. This means that countries must have some kind of process in place to allow citizens to make copies of DRMed works." (https://fsfe.org/news/2019/news-20191113-01.en.html https://fsfe.org/news/2019/news-20191113-01.en.html) Unfortunately in US the corporate has lobbied so hard to make EULA, DRM and others enforceable by law.
  - Benjamin_Dobell 6y ago
    This is the first time I've heard about this, and quite interesting to me as Article 12 of WIPO Copyright Treaty specifically requires signatories make circumvention of DRM protection devices illegal. This would seemingly be in contradiction to that. However, seems as the US, who were the driving behind this treaty, also provide exceptions/exemptions, I can see how the EU were able to justify any such contradiction. That said, from the EU directive: > Member States shall take appropriate measures to ensure that rightholders make available to the beneficiary of an exception or limitation provided for in national law in accordance with Article 5(2)(a), (2)(c), (2)(d), (2)(e), (3)(a), (3)(b) or (3)(e) the means of benefiting from that exception or limitation, to the extent necessary to benefit from that exception or limitation and where that beneficiary has legal access to the protected work or subject-matter concerned. There are certain exceptions, in articles 1, 2, 3 and 4, which can be read at https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32001L0029&from=EN https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CEL.... So there's not a blanket right to circumvent DRM; and nothing is spelt out that clearly. Additionally, not a lawyer or in Government, however, in my lay-mans reading of this directive, I'm seeing a lot of usages of the word "may". I'm (possibly incorrectly) interpreting this as meaning a Member State can introduce these copyright exceptions, not that it's mandated as the FSFE article states.
deepstack 6y ago
More and more after over 10 years working in tech I'm convinced that there is no digital system is a secure system. Hardware and Software.
- deepstack 6y ago
  what I mean by that is it really more about one's threat model. Give enough time and capable people, any system can be broken into.
vslira 6y ago
As an Apple customer I'm 100% happy with public developments like this. I really believe Apple tries to take hardware security seriously and an exploit it the open like this is surely to be addressed in the next generation of devices. Apple consumer devices have been shown to resist state-level actor threats in the past and even if current devices won't be 100% resistant forever I trust Apple to be a couple of steps ahead every gen. Of course, I'm jumping ship as soon as 100% open-source and verifiably secure HW+OS stack is available. But until then, it's Apple :P
- Tsarbomb 6y ago
  How did you get the information that apple devices resist state-level actor threats? Repeatedly state actors have broken into iphones and icloud accounts, and apple laptops are frequently the first devices to fall in the Pwn2Own contests.
  - devenblake 6y ago
    Don't know why you were downvoted, it's common knowledge that state actors can break Apple's encryption. Apple makes a huge show of refusing to break their own encryption but with a subpoena they legally have to provide the encrypted data and then state actors just go elsewhere for cracking.
    - s0ss 6y ago
      citation needed
      - callalex 6y ago
        These discussions always conflate iCloud data, including device backups, with on-device access. It is possible to use iOS without iCloud.
  - 542458 6y ago
    On the flip side, the FBI had to (probably) decap chips to get into that one shooter’s iPhone, which is pretty good security IMO.
npongratz 6y ago
> But it also breaks Apple's security platform in a big way, since this should make Apple's biometry scheme in their Macbooks much weaker and FileVault a lot easier to crack. Perhaps this unsurprising, nearly predestined exploit can convince people that they should not completely rely on biometrics for security.
stjohnswarts 6y ago
I think it's always best for these things to come out if there's a flaw. You can bet if these guys found it that China, the US government, and 11 eyes by extension all knew about it before that. It's best to know the truth, that the security is broken, rather than crossing your fingers and hoping the security works.

saurik 6y ago

So, if only Apple didn't tie the ability to repair and extend the device you purchased from them to the security of your own data, you would be able to feel a more consistent emotion with regards to interest in a fix; that seems all on Apple being a bit evil :/.

floatingatoll 6y ago
Can you describe a scenario where Touch ID is safe against evil maid attacks (say, a chip is installed allowing anyone to transmit a certain signal that spoofs Touch ID) while also allowing unrestricted modifications by someone with physical possession of the device (as this T2 rooting post celebrates)? Right now, that security is provided by Apple crypto-locking the Touch ID sensor to the T2 chip so that it cannot be modified to allow unauthorized access without being disabled altogether. With the ability to bypass the restrictions of the T2 OS, that protection is stripped away, and replaced by .. nothing, as far as I can determine. This is akin to removing your car’s electronic anti-theft system because it requires OEM keys. Sure, you can do so, but your car is a lot easier to steal, too. Only it’s not your car here, it’s your computer and all personal data on it, and all SSH keys you use to access remote servers, too. I’m all for repairability but it’s worrying that the tech community is so invested in removing a padlock that offends them that they set aside security and risk issues in favor of rooting without addressing it at all. If this complete lack of interest in device security is the best we can do, we don’t deserve repairability, and we don’t deserve root.
- the8472 6y ago
  Allow the users to install their own keys. Changing keys invalidates all encrypted/secured data. Which means you have to export the data if you do hardware changes and reimport it after supplying your own. Once you have your own keys installed you could sign additional hardware with them. If apple is a viable root of trust then you yourself should be too. There's nothing magical that only apple can do.
  - floatingatoll 6y ago
    I believe that Apple is burning their cryptographic key into readonly memory, so they would need to build out a readwrite pipeline and provide a secondary keystore option for "non-default" users that is writable by the hardware itself. That's a tall ask, but it's feasible, so we're good so far. The benefit to expert users with crypto competence is clear. How would this benefit third-party repair shops, though?
    - Nextgrid 6y ago
      The point is that you'd backup the keys in advance (when you initially set up the machine) and when the machine dies and your T2 is fried the repair shop can just replace it with a new T2, load the backed-up keys into it and give you back your machine with the data intact.
- alexvoda 6y ago
  I do not understand why you find it worrying that the tech community is invested in removing a restriction IN THE OPEN. If it can be removed for nefarious purposes, eventually, someone will do so and sell the exploit on the zero-day market (probably to a state actor). The existence of the vulnerability is just a fact, it is reality. Why do you feel safer not knowing about it? Whether you know about it or not the vulnerability is still there.
  - floatingatoll 6y ago
    I do not ‘feel safer not knowing about it’. I feel safer knowing how to DFU a T2 Mac, though. It’s turning out to be very useful knowledge over time. I encourage you to learn how too.
fastball 6y ago
AFAIK, it's not just about the security of your data (you don't need a T2 chip to encrypt data), but also about discouraging theft of the hardware itself. In light of that, how do you allow for components to be swapped out wholesale without breaking the security model? Isn't the entire point that you can't just steal a Macbook, swap out the SSD, and now you have a functioning (stolen) laptop?
- the8472 6y ago
  The initial transition from the apple root of trust to your own root (which you would then use to install new hardware) could require being authenticated, this way a thief couldn't do it while the legitimate owner could.
  - fastball 6y ago
    That's a route I hadn't thought of. Seems like a great idea!
- dividedbyzero 6y ago
  You can also get away with a much weaker passphrase if you can somehow rate-limit brute force attacks. As I understand it that's one of the things the T2 does, you can't authenticate except through the T2, and the T2 will slow you down and lock you out after n tries. And I think that's actually incredibly underappreciated feature, most people are both bad at memorizing long, complex passwords/passphrases and not all that motivated since the threat is quite abstract. I've had a hard time convincing some people to have any sort of password at all on their laptop (that they travel with, work in all sorts of places and are overall pretty careless with), as it carries the risk of forgetting the password and it's cumbersome and inconvenient compared to being able to simply open the computer to a logged-in desktop. Making security less of a hassle really does help with adoption. Having a short, relatively weak, but not trivial password is way way better than having none at all, and realistically that's all most people are ever going to have, so making those passwords hold up better is a really smart move that instantly ups the security of lots and lots of people out there. But that's not something I believe you could do without a scheme like tieing the encrypted data to a complex secret inside a specific T2 that is uncracked, otherwise you could simply put the SSD in another computer and brute-force it there.

tinus_hn 6y ago

If it really matters, Apple can bring an update that blocks these attacks. If the system depends on security through obscurity, sorry, that never lasts.

saagarjha 6y ago
Apple cannot update this away; the vulnerability goes down to the very lowest levels of the software to the code burned into ROM.
- selectodude 6y ago
  They were able to update it away on the iPhone X. Checkrain doesn’t work on iOS 14 anymore.
  - saagarjha 6y ago
    Well, somewhat. They’re doing a clever side channel based on the SEP’s RNG to panic the device when booting from DFU, but this has already been bypassed on older devices via a bug in SEPROM. I believe they already have code execution in the A11’s enclave as well, but that one has some sort of replay protection that complicates matters.

Benjamin_Dobell 6y ago

Apple did actually screw the pooch on this one. Typically, it's criminally illegal to circumvent DRM in the US (and 99% of the rest of the world). However, there are also certain exemptions that have been granted, within the US only (other countries are not so lucky). The right to repair is one such exemption[1]. If Apple had separated security from first-party repair enforcement, then anyone found even attempting to break the T2 chip might have been up for jail time. However, the right to repair is a valid defense. Of course, making circumvention criminally illegal doesn't make the chip itself any more technically secure; say against criminals. It is a pretty solid deterrent though. [1] https://www.copyright.gov/1201/2018/ https://www.copyright.gov/1201/2018/

Daniel_sk 6y ago
I bet breaking DRM is legal in most parts of the world. Good luck to any company trying to sue an individual for breaking DRM. "Article 6.4 of the European Directive mandates Member States to ensure users can benefit from the copyright exceptions. This means that countries must have some kind of process in place to allow citizens to make copies of DRMed works." (https://fsfe.org/news/2019/news-20191113-01.en.html https://fsfe.org/news/2019/news-20191113-01.en.html) Unfortunately in US the corporate has lobbied so hard to make EULA, DRM and others enforceable by law.
- Benjamin_Dobell 6y ago
  This is the first time I've heard about this, and quite interesting to me as Article 12 of WIPO Copyright Treaty specifically requires signatories make circumvention of DRM protection devices illegal. This would seemingly be in contradiction to that. However, seems as the US, who were the driving behind this treaty, also provide exceptions/exemptions, I can see how the EU were able to justify any such contradiction. That said, from the EU directive: > Member States shall take appropriate measures to ensure that rightholders make available to the beneficiary of an exception or limitation provided for in national law in accordance with Article 5(2)(a), (2)(c), (2)(d), (2)(e), (3)(a), (3)(b) or (3)(e) the means of benefiting from that exception or limitation, to the extent necessary to benefit from that exception or limitation and where that beneficiary has legal access to the protected work or subject-matter concerned. There are certain exceptions, in articles 1, 2, 3 and 4, which can be read at https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32001L0029&from=EN https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CEL.... So there's not a blanket right to circumvent DRM; and nothing is spelt out that clearly. Additionally, not a lawyer or in Government, however, in my lay-mans reading of this directive, I'm seeing a lot of usages of the word "may". I'm (possibly incorrectly) interpreting this as meaning a Member State can introduce these copyright exceptions, not that it's mandated as the FSFE article states.

deepstack 6y ago

More and more after over 10 years working in tech I'm convinced that there is no digital system is a secure system. Hardware and Software.

deepstack 6y ago
what I mean by that is it really more about one's threat model. Give enough time and capable people, any system can be broken into.

vslira 6y ago

As an Apple customer I'm 100% happy with public developments like this. I really believe Apple tries to take hardware security seriously and an exploit it the open like this is surely to be addressed in the next generation of devices. Apple consumer devices have been shown to resist state-level actor threats in the past and even if current devices won't be 100% resistant forever I trust Apple to be a couple of steps ahead every gen. Of course, I'm jumping ship as soon as 100% open-source and verifiably secure HW+OS stack is available. But until then, it's Apple :P

Tsarbomb 6y ago
How did you get the information that apple devices resist state-level actor threats? Repeatedly state actors have broken into iphones and icloud accounts, and apple laptops are frequently the first devices to fall in the Pwn2Own contests.
- devenblake 6y ago
  Don't know why you were downvoted, it's common knowledge that state actors can break Apple's encryption. Apple makes a huge show of refusing to break their own encryption but with a subpoena they legally have to provide the encrypted data and then state actors just go elsewhere for cracking.
  - s0ss 6y ago
    citation needed
    - callalex 6y ago
      These discussions always conflate iCloud data, including device backups, with on-device access. It is possible to use iOS without iCloud.
- 542458 6y ago
  On the flip side, the FBI had to (probably) decap chips to get into that one shooter’s iPhone, which is pretty good security IMO.

npongratz 6y ago

> But it also breaks Apple's security platform in a big way, since this should make Apple's biometry scheme in their Macbooks much weaker and FileVault a lot easier to crack. Perhaps this unsurprising, nearly predestined exploit can convince people that they should not completely rely on biometrics for security.

stjohnswarts 6y ago

I think it's always best for these things to come out if there's a flaw. You can bet if these guys found it that China, the US government, and 11 eyes by extension all knew about it before that. It's best to know the truth, that the security is broken, rather than crossing your fingers and hoping the security works.