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I’ve heard some people taking about using a raspberry pi zero or some other microcomputer to apply the exploit on boot, which sounds quite interesting. As some

by jpxw 7y ago

I’ve heard some people taking about using a raspberry pi zero or some other microcomputer to apply the exploit on boot, which sounds quite interesting. As someone who used to jailbreak back in the day, this news was really exciting. However looking at it in a mature way than I did back then, it’s also slightly worrying that a whole class of iOS devices have a severe and unpatchable security flaw.

StavrosK 7y ago
Why is that? I've long been against Apple's stance of not allowing me access to the hardware I own, and this exploit seems the best of both worlds: If you want to make sure you're secure, just reboot the phone.
- mentat 7y ago
  If you can access using this so can others when you cross borders, are stopped by police, have spying spouse, etc. Those are real and sometimes fatal threat models.
  - deleted 7y ago
    [deleted]
  - fullonrager 7y ago
    If law enforcement did take your device, it would be useless if you have a passcode. Your data will still be encrypted.
    - deleted 7y ago
      [deleted]
    - gruez 7y ago
      depends on whether exploiting the bootrom allows you bypass the anti-hammering mechanism, or the "wipe data after 10 failed attempts" mechanism. A 6 digit passcode by itself is very easy to crack.
      - StavrosK 7y ago
        It doesn't. Just reboot the phone and it's secure.
        gruez 7y ago
        I think you misunderstood the threat model. The concern is that they seized your phone, used the exploit to bypass the "normal" passcode protections, allowing them to bruteforce your 6 digit passcode in hours/days rather than years/decades/never (if you had the wipe after 10 failed attempts enabled).
        StavrosK 7y ago
        That is not possible, the key is inside a hardware chip which enforces the number of tries for the PIN.
        fragmede 7y ago
        Now they do. That wasn't always the case though, for those on older devices (Anything older than the 5s, I believe), or older iOS versions.
      - morpheuskafka 7y ago
        IIRC from the San Bernardino case, that was the case on the shooter's phone (a 5S I think), but since then it has been built in to the "Secure Enclave" chip which is not affected by the vulnerability. But you could flash a fake iOS that logged the user's code and/or directly exfiltrated the data--the user would have no idea that it was not the stock iOS they were giving their code to. It would leave them which a bricked device the next time they rebooted, which could raise suspicions.
        earenndil 7y ago
        It was a 5c; 5s and later had the SEP. You don't 'flash' a fake ios; you can use the bootrom exploit to put your modified version of ios into memory, and once you reboot you would get back straight stock ios. They could even make it reboot as soon as the password was harvested, leaving behind no trace. This is scary stuff. You can keep yourself safe by rebooting as soon as you get your phone back from border patrol, but many people would not know to do that.
- paulcole 7y ago
  My take is that you’re misinterpreting what you (theoretically) have purchased. You bought an iPhone, not a pile of hardware. Nowhere in the transaction did Apple misrepresent what they offered. Your wish for iPhone shaped hardware that is yours to do whatever you want with doesn’t change the fact that this isn’t what’s for sale.
  - StavrosK 7y ago
    How do you reconcile the fact that I've bought it with the fact that it's not "mine to do whatever I want with"? Ownership is the state of exclusive rights and control over property, which I don't have when I buy an Apple device. Either they shouldn't say they're selling it (they can say they're leasing it to me) or they should give me all rights.
    - lotsofpulp 7y ago
      World isn’t so black and white. There are restrictions on many things you “own”. Land, certain chemicals, technologies, etc. I like to think of “owning” in the developed world simply as a right to collect rent from someone else.
      - StavrosK 7y ago
        > There are restrictions on many things you “own”. Are any of these restrictions there so a private third party can decide what you do with your property?
        edoceo 7y ago
        Yes, land rights for example. Someone else decides what you're allowed to build and/or dig.
        StavrosK 7y ago
        Which private party decides that?
- ralfd 7y ago
  If you lost your iPhone or it was stolen it was just a worthless brick for the finder/thief. Think about what a big peace of mind that is! This changed now for older hardware.
  - blattimwind 7y ago
    It didn't, because the encryption keys are in the secure coprocessor.
    - oarsinsync 7y ago
      Your data is protected, but the iCloud activation lock can be bypassed. Hence it no longer being a brick.
      - tptacek 7y ago
        What's the market value of a phone that has to be put into firmware upgrade mode every time it restarts?
        oarsinsync 7y ago
        TBD. Check out eBay in the coming months, I’m sure a value will be determined soon. It’s definitely higher than what it is now (sold as scrap for parts)
ethbro 7y ago
> it’s also slightly worrying that a whole class of iOS devices have a severe and unpatchable security flaw. "Severe" is a bit over-dramatic. To be accurate, from the article: Checkm8 requires physical access to the phone. It can't be remotely executed, even if combined with other exploits The exploit allows only tethered jailbreaks, meaning it lacks persistence. The exploit must be run each time an iDevice boots. Checkm8 doesn't bypass the protections offered by the Secure Enclave and Touch ID.
- matwood 7y ago
  > "Severe" is a bit over-dramatic. To be accurate, from the article: Agreed. The hyperbole yesterday was millions of iPhones now have no security which does not seem to be the case. For the average user nothing has changed. For the paranoid, reboot the phone if it ever leaves your sight.
  - owl57 7y ago
    It's not easy to pull battery out, so we are left with a force-reboot button chord. That feature is probably meant to protect from normal, non-malicious bugs. How sure can the hypothetical paranoid be that the phone has indeed rebooted and not faked it?
    - givinguflac 7y ago
      The hypothetical user can be certain if they simply do a force reboot by holding power and volume, instead of shutting down using the power button long press and touch screen swipe.
      - mtsr 7y ago
        Why? Is there any way to be certain these are done in hardware and can’t be caught in a low level system once the device is rooted? It’s a black box, so no way to know until somebody manages to pull it off.
        7y ago
morpheuskafka 7y ago
My suggestion is to build it into a battery case. Then you always have the device with you and it's always charged if your phone is, preventing catastrophic dead phone in the desert scenarios.
morcheeba 7y ago
It might be patchable, even though it's in ROM. The ARM chip I've been working on has a mechanism to change a few words in ROM by blowing fuses... basically, between the ROM and the CPU sits a device that compares addresses and if matches what's found in the fuses, will replace the data being read. Since it doesn't have to be fast (since ROM code is only used at boot and there isn't a lot of it), they can slow down memory access to get more security.
- floatboth 7y ago
  Apple would've very likely patched it a long time ago if it was patchable, since the newest devices' ROMs don't have the bugs anymore. Having a completely 100% untouchable ROM is very valuable. Yes, this kind of exploit being permanent is the downside, but then they don't have to worry about the modification fuses being misused in any way ever.

by jpxw 7y ago

StavrosK 7y ago

Why is that? I've long been against Apple's stance of not allowing me access to the hardware I own, and this exploit seems the best of both worlds: If you want to make sure you're secure, just reboot the phone.

mentat 7y ago
If you can access using this so can others when you cross borders, are stopped by police, have spying spouse, etc. Those are real and sometimes fatal threat models.
- deleted 7y ago
  [deleted]
- fullonrager 7y ago
  If law enforcement did take your device, it would be useless if you have a passcode. Your data will still be encrypted.
  - deleted 7y ago
    [deleted]
  - gruez 7y ago
    depends on whether exploiting the bootrom allows you bypass the anti-hammering mechanism, or the "wipe data after 10 failed attempts" mechanism. A 6 digit passcode by itself is very easy to crack.
    - StavrosK 7y ago
      It doesn't. Just reboot the phone and it's secure.
      - gruez 7y ago
        I think you misunderstood the threat model. The concern is that they seized your phone, used the exploit to bypass the "normal" passcode protections, allowing them to bruteforce your 6 digit passcode in hours/days rather than years/decades/never (if you had the wipe after 10 failed attempts enabled).
        StavrosK 7y ago
        That is not possible, the key is inside a hardware chip which enforces the number of tries for the PIN.
        fragmede 7y ago
        Now they do. That wasn't always the case though, for those on older devices (Anything older than the 5s, I believe), or older iOS versions.
    - morpheuskafka 7y ago
      IIRC from the San Bernardino case, that was the case on the shooter's phone (a 5S I think), but since then it has been built in to the "Secure Enclave" chip which is not affected by the vulnerability. But you could flash a fake iOS that logged the user's code and/or directly exfiltrated the data--the user would have no idea that it was not the stock iOS they were giving their code to. It would leave them which a bricked device the next time they rebooted, which could raise suspicions.
      - earenndil 7y ago
        It was a 5c; 5s and later had the SEP. You don't 'flash' a fake ios; you can use the bootrom exploit to put your modified version of ios into memory, and once you reboot you would get back straight stock ios. They could even make it reboot as soon as the password was harvested, leaving behind no trace. This is scary stuff. You can keep yourself safe by rebooting as soon as you get your phone back from border patrol, but many people would not know to do that.
paulcole 7y ago
My take is that you’re misinterpreting what you (theoretically) have purchased. You bought an iPhone, not a pile of hardware. Nowhere in the transaction did Apple misrepresent what they offered. Your wish for iPhone shaped hardware that is yours to do whatever you want with doesn’t change the fact that this isn’t what’s for sale.
- StavrosK 7y ago
  How do you reconcile the fact that I've bought it with the fact that it's not "mine to do whatever I want with"? Ownership is the state of exclusive rights and control over property, which I don't have when I buy an Apple device. Either they shouldn't say they're selling it (they can say they're leasing it to me) or they should give me all rights.
  - lotsofpulp 7y ago
    World isn’t so black and white. There are restrictions on many things you “own”. Land, certain chemicals, technologies, etc. I like to think of “owning” in the developed world simply as a right to collect rent from someone else.
    - StavrosK 7y ago
      > There are restrictions on many things you “own”. Are any of these restrictions there so a private third party can decide what you do with your property?
      - edoceo 7y ago
        Yes, land rights for example. Someone else decides what you're allowed to build and/or dig.
        StavrosK 7y ago
        Which private party decides that?
ralfd 7y ago
If you lost your iPhone or it was stolen it was just a worthless brick for the finder/thief. Think about what a big peace of mind that is! This changed now for older hardware.
- blattimwind 7y ago
  It didn't, because the encryption keys are in the secure coprocessor.
  - oarsinsync 7y ago
    Your data is protected, but the iCloud activation lock can be bypassed. Hence it no longer being a brick.
    - tptacek 7y ago
      What's the market value of a phone that has to be put into firmware upgrade mode every time it restarts?
      - oarsinsync 7y ago
        TBD. Check out eBay in the coming months, I’m sure a value will be determined soon. It’s definitely higher than what it is now (sold as scrap for parts)

ethbro 7y ago

> it’s also slightly worrying that a whole class of iOS devices have a severe and unpatchable security flaw. "Severe" is a bit over-dramatic. To be accurate, from the article: Checkm8 requires physical access to the phone. It can't be remotely executed, even if combined with other exploits The exploit allows only tethered jailbreaks, meaning it lacks persistence. The exploit must be run each time an iDevice boots. Checkm8 doesn't bypass the protections offered by the Secure Enclave and Touch ID.

matwood 7y ago
> "Severe" is a bit over-dramatic. To be accurate, from the article: Agreed. The hyperbole yesterday was millions of iPhones now have no security which does not seem to be the case. For the average user nothing has changed. For the paranoid, reboot the phone if it ever leaves your sight.
- owl57 7y ago
  It's not easy to pull battery out, so we are left with a force-reboot button chord. That feature is probably meant to protect from normal, non-malicious bugs. How sure can the hypothetical paranoid be that the phone has indeed rebooted and not faked it?
  - givinguflac 7y ago
    The hypothetical user can be certain if they simply do a force reboot by holding power and volume, instead of shutting down using the power button long press and touch screen swipe.
    - mtsr 7y ago
      Why? Is there any way to be certain these are done in hardware and can’t be caught in a low level system once the device is rooted? It’s a black box, so no way to know until somebody manages to pull it off.
      - 7y ago

morpheuskafka 7y ago

My suggestion is to build it into a battery case. Then you always have the device with you and it's always charged if your phone is, preventing catastrophic dead phone in the desert scenarios.

morcheeba 7y ago

It might be patchable, even though it's in ROM. The ARM chip I've been working on has a mechanism to change a few words in ROM by blowing fuses... basically, between the ROM and the CPU sits a device that compares addresses and if matches what's found in the fuses, will replace the data being read. Since it doesn't have to be fast (since ROM code is only used at boot and there isn't a lot of it), they can slow down memory access to get more security.

floatboth 7y ago
Apple would've very likely patched it a long time ago if it was patchable, since the newest devices' ROMs don't have the bugs anymore. Having a completely 100% untouchable ROM is very valuable. Yes, this kind of exploit being permanent is the downside, but then they don't have to worry about the modification fuses being misused in any way ever.