4 ms·

> I suspect that this will be added to all Google Play integrity levels, limiting many apps from being installed on unpatched phones in the future. You do real

by kuschku 3mo ago

> I suspect that this will be added to all Google Play integrity levels, limiting many apps from being installed on unpatched phones in the future. You do realize that a full kernel vulnerability like this allows you to feed falsified information to SafetyNet? Just like DRM, it gives the developer the illusion of control, but doesn't do anything to actually improve "safety" or "integrity". It's silly that whenever I see a vulnerability like this, all I can think about is "finally, a way to get control over my own devices back". Once again, Stallman was right. https://www.gnu.org/philosophy/right-to-read.en.html https://www.gnu.org/philosophy/right-to-read.en.html Personally, I'll use this to root my Android TV and Chromecast devices and remove the shitty ads in the launcher (which Google added after I bought the devices!).

goodburb 3mo ago
Agreed, but I think this will force the average user to upgrade* their phones after losing access to sensitive apps (bank, gov) before getting compromised. Good news for reusing old phones and taking control. *as in replace
- karteum 3mo ago
  "this will force the average user to upgrade their phones" A lot of phones don't receive any upgrades after 1 or 2 years... I wish that Google would have forced vendors to implement a proper hardware abstraction (uefi or similar) so that a single kernel could run on any smartphone, just like it's the case for PCs...
  - charcircuit 3mo ago
    Google has required vendors to do that since Android 12. For a given version that same exact kernel is used on all phones with that version. https://source.android.com/docs/core/architecture/kernel/generic-kernel-image https://source.android.com/docs/core/architecture/kernel/gen...
    - ChocolateGod 3mo ago
      Unfortunately it still requires OEMs to ship that kernel.
- kuschku 3mo ago
  We should be fighting against SafetyNet and similar attestation systems. The proper solution is one we had with desktop computing for decades. If you keep the key material on your eID or bank card, you don't need a locked down operating system. Which then allows devices to live for much longer. We're slowly losing the war on General Purpose Computing. https://media.ccc.de/v/28c3-4848-en-the_coming_war_on_general_computation https://media.ccc.de/v/28c3-4848-en-the_coming_war_on_genera...
  - ChocolateGod 3mo ago
    > We should be fighting against SafetyNet and similar attestation systems. The proper solution is one we had with desktop computing for decades. If you keep the key material on your eID or bank card So you want a bank card/ID card to be required each time you use Google Pay? What's the point of Google Pay then.
    - kuschku 3mo ago
      Once upon a time(tm), Google had a great solution for that: You could get a credit card in nano SIM format, and insert into in your dual-SIM phone. That then allows you to do secure NFC credit card payments even on a rooted phone with custom ROM.
      - skinfaxi 3mo ago
        Do you have more details on the sim credit card?
      - inigyou 3mo ago
        I think some banks still do this with NFC instead?
      - ChocolateGod 3mo ago
        That doesn't work when someone has multiple or virtual cards. That also means if someone steals my phone they get my credit card too. Not a great solution.
- AnthonyMouse 3mo ago
  > Agreed, but I think this will force the average user to upgrade* their phones after losing access to sensitive apps (bank, gov) before getting compromised. The problem being that there are many millions of people who can't afford to replace a phone they only recently bought just because the vendor never updates it, which means those banks and things can't in practice demand that people do that. Indeed, it creates the opposite problem, because installing a custom ROM on that device would give it a patched kernel but cause it to fail attestation, so what the attestation is actually doing is requiring those people to continue to use the vulnerable OS.
didntcheck 3mo ago
> You do realize that a full kernel vulnerability like this allows you to feed falsified information to SafetyNet? Are you sure that's true? The whole reason why modern Safetynet/Play Integrity uses HSM data where possible is that you can't spoof that with root (without a microcode bug). It does not trust the running OS by design I just tried GrapheneOS's https://attestation.app/ https://attestation.app/ on a stock Pixel, and all of the OS version info shows in the "hardware verified" section
- kuschku 3mo ago
  There's a lot of confusion around attestation, some of which is IMO done intentionally. First there is Android's attestation framework. That does actual hardware attestation, as used by GrapheneOS, and supported by literally no app whatsoever. Then there is SafetyNet, now Play Integrity. Depending on what level of integrity checking is being done, this will do a combination of cursory surface-level software checks, delegation to the aforementioned hardware attestation framework, and several other checks. Importantly, SafetyNet/Play Integrity rejects some devices that pass hardware attestation (e.g., Graphene OS), and accepts some devices that fail hardware attestation (fairphone, many cheaper devices with broken ROMs, etc). e.g., fairphone leaked the private key for their attestation, but many of their devices still pass SafetyNet, while some other devices that pass attestation but have known bootloader flaws are blocked by SafetyNet. Because this isn't strict cryptographic verification, but a mess of heuristics and guesswork, it's a constant cat and mouse game. What Google really achieved here is to make it expensive enough that no casual user can bypass it to e.g. cheat in Pokemon Go, but only a determined attacker has a chance. And with "determined attacker" I'm not just talking about states, but even e.g. movie pirates breaking DRM to rip Netflix movies. Of course, even full cryptographic attestation isn't perfect, and can be bypassed with enough effort. As shown by the famous iPhone hardware jailbreak, where you drill into the SoC and solder directly to the CPU's internal wiring.

by kuschku 3mo ago

goodburb 3mo ago

Agreed, but I think this will force the average user to upgrade* their phones after losing access to sensitive apps (bank, gov) before getting compromised. Good news for reusing old phones and taking control. *as in replace

karteum 3mo ago
"this will force the average user to upgrade their phones" A lot of phones don't receive any upgrades after 1 or 2 years... I wish that Google would have forced vendors to implement a proper hardware abstraction (uefi or similar) so that a single kernel could run on any smartphone, just like it's the case for PCs...
- charcircuit 3mo ago
  Google has required vendors to do that since Android 12. For a given version that same exact kernel is used on all phones with that version. https://source.android.com/docs/core/architecture/kernel/generic-kernel-image https://source.android.com/docs/core/architecture/kernel/gen...
  - ChocolateGod 3mo ago
    Unfortunately it still requires OEMs to ship that kernel.
kuschku 3mo ago
We should be fighting against SafetyNet and similar attestation systems. The proper solution is one we had with desktop computing for decades. If you keep the key material on your eID or bank card, you don't need a locked down operating system. Which then allows devices to live for much longer. We're slowly losing the war on General Purpose Computing. https://media.ccc.de/v/28c3-4848-en-the_coming_war_on_general_computation https://media.ccc.de/v/28c3-4848-en-the_coming_war_on_genera...
- ChocolateGod 3mo ago
  > We should be fighting against SafetyNet and similar attestation systems. The proper solution is one we had with desktop computing for decades. If you keep the key material on your eID or bank card So you want a bank card/ID card to be required each time you use Google Pay? What's the point of Google Pay then.
  - kuschku 3mo ago
    Once upon a time(tm), Google had a great solution for that: You could get a credit card in nano SIM format, and insert into in your dual-SIM phone. That then allows you to do secure NFC credit card payments even on a rooted phone with custom ROM.
    - skinfaxi 3mo ago
      Do you have more details on the sim credit card?
    - inigyou 3mo ago
      I think some banks still do this with NFC instead?
    - ChocolateGod 3mo ago
      That doesn't work when someone has multiple or virtual cards. That also means if someone steals my phone they get my credit card too. Not a great solution.
AnthonyMouse 3mo ago
> Agreed, but I think this will force the average user to upgrade* their phones after losing access to sensitive apps (bank, gov) before getting compromised. The problem being that there are many millions of people who can't afford to replace a phone they only recently bought just because the vendor never updates it, which means those banks and things can't in practice demand that people do that. Indeed, it creates the opposite problem, because installing a custom ROM on that device would give it a patched kernel but cause it to fail attestation, so what the attestation is actually doing is requiring those people to continue to use the vulnerable OS.

didntcheck 3mo ago

> You do realize that a full kernel vulnerability like this allows you to feed falsified information to SafetyNet? Are you sure that's true? The whole reason why modern Safetynet/Play Integrity uses HSM data where possible is that you can't spoof that with root (without a microcode bug). It does not trust the running OS by design I just tried GrapheneOS's https://attestation.app/ https://attestation.app/ on a stock Pixel, and all of the OS version info shows in the "hardware verified" section

kuschku 3mo ago
There's a lot of confusion around attestation, some of which is IMO done intentionally. First there is Android's attestation framework. That does actual hardware attestation, as used by GrapheneOS, and supported by literally no app whatsoever. Then there is SafetyNet, now Play Integrity. Depending on what level of integrity checking is being done, this will do a combination of cursory surface-level software checks, delegation to the aforementioned hardware attestation framework, and several other checks. Importantly, SafetyNet/Play Integrity rejects some devices that pass hardware attestation (e.g., Graphene OS), and accepts some devices that fail hardware attestation (fairphone, many cheaper devices with broken ROMs, etc). e.g., fairphone leaked the private key for their attestation, but many of their devices still pass SafetyNet, while some other devices that pass attestation but have known bootloader flaws are blocked by SafetyNet. Because this isn't strict cryptographic verification, but a mess of heuristics and guesswork, it's a constant cat and mouse game. What Google really achieved here is to make it expensive enough that no casual user can bypass it to e.g. cheat in Pokemon Go, but only a determined attacker has a chance. And with "determined attacker" I'm not just talking about states, but even e.g. movie pirates breaking DRM to rip Netflix movies. Of course, even full cryptographic attestation isn't perfect, and can be bypassed with enough effort. As shown by the famous iPhone hardware jailbreak, where you drill into the SoC and solder directly to the CPU's internal wiring.