5 ms·

> There is custom silicon in every recent iPhone that does nothing but stop modification of kernel code, even in the face of code execution and arbitrary read/w

> There is custom silicon in every recent iPhone that does nothing but stop modification of kernel code, even in the face of code execution and arbitrary read/write in EL1: interesting from an academic standpoint, but if you stop and think about it for more than a second it's entirely useless for actually protecting users. Every single malware (or jailbreak) wants to modify EL1 code, it's not just interesting from an academic standpoint.

saagarjha 6y ago
Malware has no need to modify EL1 code if it can grab your iMessages without doing so; exploit chains found in the wild grab the kernel task port (or equivalent) instead. Jailbreaks do want to modify EL1 code, but this comes back to the point I was making about this protecting Apple's software and not their users.
- judge2020 6y ago
  To be fair, malware could also modify the kernel and achieve the same effect, so it does provide one step towards security and protecting the user.
  - saagarjha 6y ago
    There's no reason for malware to do this, though. It's like putting reinforcing your back door so people can't kick it in while leaving the front door with a pickable lock.
    - stouset 6y ago
      Except the front door doesn’t have a pickable lock, and this is just one of many overlapping security mechanisms. It’s like installing a metal back door and front door, bolting them, and also locking your windows. Just because the windows can be broken more easily by an invader doesn’t mean there isn’t also value in the other steps you took.
      - saagarjha 6y ago
        > It’s like installing a metal back door and front door, bolting them, and also locking your windows. Except Apple hasn't done that, they have just reinforced the back door and left the front door (which has periodically been picked) open. As it stands now it mostly just exists to annoy jailbreakers.
        stouset 6y ago
        iOS has probably the best security record of any widespread consumer operating system in history. Certainly better than Windows and Android.
        shi314 6y ago
        Apple Software is not secure either. Apple has just marketed themselves as being more secure. https://googleprojectzero.blogspot.com/2019/08/a-very-deep-dive-into-ios-exploit.html?m=1 https://googleprojectzero.blogspot.com/2019/08/a-very-deep-d...
        nodamage 6y ago
        No platform is perfectly secure and every single piece of software is potentially vulnerable to zero-day exploits. The important question, as the previous commenter said, is what is the security record of each platform? And iOS is miles ahead of everyone else: Among smartphones, Android™ devices are the most commonly targeted by malware. In mobile networks, Android devices were responsible for 47.15% of the observed malware infections, Windows©/ PCs for 35.82%, IoT for 16.17% and iPhones© for less than 1%. Source: Nokia's latest threat intelligence whitepaper (https://onestore.nokia.com/asset/205835 https://onestore.nokia.com/asset/205835) Apple also has a much better track record when it comes to providing long term security updates for the devices it sells.
        pjmlp 6y ago
        While I agree that iPhones are more secure, one should also take into account that they represent around 20% of deployed phone devices across the world.

saagarjha 6y ago

Malware has no need to modify EL1 code if it can grab your iMessages without doing so; exploit chains found in the wild grab the kernel task port (or equivalent) instead. Jailbreaks do want to modify EL1 code, but this comes back to the point I was making about this protecting Apple's software and not their users.

judge2020 6y ago
To be fair, malware could also modify the kernel and achieve the same effect, so it does provide one step towards security and protecting the user.
- saagarjha 6y ago
  There's no reason for malware to do this, though. It's like putting reinforcing your back door so people can't kick it in while leaving the front door with a pickable lock.
  - stouset 6y ago
    Except the front door doesn’t have a pickable lock, and this is just one of many overlapping security mechanisms. It’s like installing a metal back door and front door, bolting them, and also locking your windows. Just because the windows can be broken more easily by an invader doesn’t mean there isn’t also value in the other steps you took.
    - saagarjha 6y ago
      > It’s like installing a metal back door and front door, bolting them, and also locking your windows. Except Apple hasn't done that, they have just reinforced the back door and left the front door (which has periodically been picked) open. As it stands now it mostly just exists to annoy jailbreakers.
      - stouset 6y ago
        iOS has probably the best security record of any widespread consumer operating system in history. Certainly better than Windows and Android.
        shi314 6y ago
        Apple Software is not secure either. Apple has just marketed themselves as being more secure. https://googleprojectzero.blogspot.com/2019/08/a-very-deep-dive-into-ios-exploit.html?m=1 https://googleprojectzero.blogspot.com/2019/08/a-very-deep-d...
        nodamage 6y ago
        No platform is perfectly secure and every single piece of software is potentially vulnerable to zero-day exploits. The important question, as the previous commenter said, is what is the security record of each platform? And iOS is miles ahead of everyone else: Among smartphones, Android™ devices are the most commonly targeted by malware. In mobile networks, Android devices were responsible for 47.15% of the observed malware infections, Windows©/ PCs for 35.82%, IoT for 16.17% and iPhones© for less than 1%. Source: Nokia's latest threat intelligence whitepaper (https://onestore.nokia.com/asset/205835 https://onestore.nokia.com/asset/205835) Apple also has a much better track record when it comes to providing long term security updates for the devices it sells.
        pjmlp 6y ago
        While I agree that iPhones are more secure, one should also take into account that they represent around 20% of deployed phone devices across the world.