Stolen phone

[deleted]

ErminioOttone BFU = before first unlock, after restart, data at rest

AFU = after first unlock, subsequent state, apps running

Sorry MBS beat me to it :)

matchboxbananasynergy

ErminioOttone But that it is the same on all phones, where is the difference with a classical pixel ? In a classical pixel you will need to do factory reset to access to the phone (let me be clear, by access to the phone I mean use it as a new brand one so no datas from you)

In that regard, there is no difference. The thief having a usable device after they steal it isn't the goal here. The goal is taking steps to try and ensure that all of your data cannot be accessed by someone who steals your phone. Your phone being stolen is one thing, someone being able to unlock it and access everything you have inside the phone is much, much worse.

ErminioOttone

matchboxbananasynergy Ok so on that we do agree, the next thing is how the GOS provide a better privacy/security against some possible attacks with respect to a classical Pixel or android users. There a lot of videos on youtube talking about GOS however it is rare to have a practical example on how there is this real upgrade in terms of better protection against any possible attack if we compare to a classical android device. Is there any chance that GOS team do some sort of technical video proof comparing an attack example (bruteforce, pc debbug, usb malware....) to see how GOS behave against such attacks and how a classical Pixel, or samsung behave or why not, apple devices ?

ErminioOttone

matchboxbananasynergy But when I reboot the phone (or just snooze it) and I have to unlock it (we are not talking about the SIM password, right) I can do that by PIN/Password/fingerprint/face scan. I am aware of course that if the phone is unlocked (you can access to my apps, make calls, photos and so on) well you have access to everything

matchboxbananasynergy

ErminioOttone No, we are not talking about the SIM PIN.

Yes, even after the first unlock, you still have to use a password to access everything. Normally.

Please refer to what I am saying above. When the phone is in AFU state, the data is not encrypted and an OS exploit can get you access to that data. That is not the case when the device is in BFU mode, which is why you want the device to get to that state as quickly as possible.

Maybe an example will help you understand.

Please watch https://www.youtube.com/watch?v=dSgSnYPgzT0 (note that despite the title, this was NOT specific to Pixels and affected basically all Android phones across multiple Android versions).

Even though the phone is locked there, the device has already been unlocked once after a reboot. Therefore, it is in the AFU state. As such, with this exploit, they are able to bypass the lockscreen and get in and access the phone's data.

If the phone had been rebooted and not unlocked for the first time (BFU state), then this exploit does nothing even if attempted, because the data is completely encrypted and at rest.

I hope that helps understand the difference.

ErminioOttone

matchboxbananasynergy Thanks for you detailed information. However I am kind of suprised, on my phone even after a reboot I have just one step to unlock the phone that is the pin/password/fingerpint to unlock the screen (and so the phone).

For my comprehension: BFU is when the screen is locked and AFU is when you unlocked everything. But as I understand that's not totally the case. I don't see what are the differences since I still have to insert the same unique password not matter if I reboot or just snooze the screen.

P.s : I wasn't aware that this trick was working also on other devices but just on pixels 6

Probably9857

ErminioOttone
BFU/AFU refers to "before/after FIRST unlock". Meaning the first unlock after a reboot.

BFU = rebooted, never unlocked
AFU = rebooted, unlocked, locked again

matchboxbananasynergy

ErminioOttone Thanks for you detailed information. However I am kind of suprised, on my phone even after a reboot I have just one step to unlock the phone that is the pin/password/fingerpint to unlock the screen (and so the phone).

Reboot your phone. You will see that the first time you try to unlock it, it will not let you use your fingerprint. Try it.

ErminioOttone I don't see what are the differences since I still have to insert the same unique password not matter if I reboot or just snooze the screen.

The difference is that in BFU the data is encrypted at rest...

ErminioOttone P.s : I wasn't aware that this trick was working also on other devices but just on pixels 6

To be clear, this is now fixed, but yes, it didn't just affect Pixels, but all phones in multiple Android versions until it was patched.

ErminioOttone

matchboxbananasynergy Reboot your phone. You will see that the first time you try to unlock it, it will not let you use your fingerprint. Try it.

I tried but there are no differences in unlocking it by password or fingerprint. I might have a too old (for sure) phone. Anyway thanks you a lot for taking the time to reply to my questions :)

[deleted]

ErminioOttone to answer your original question, yes, it is okay not having a password to prompt a restart because doing that would put all data at rest rendering them inaccessible. Which would happen within the next three days anyway (auto reboot) if you have set it to default.

Xtreix

ErminioOttone I tried but there are no differences in unlocking it by password or fingerprint. I might have a too old (for sure) phone.

Hello and welcome.

I've never used Samsung phones, so maybe it's different on your device, but on GrapheneOS on a supported Pixel, when you boot or reboot the device without unlocking it, the device is in BFU mode (before first unlock) the point of BFU is that data is encrypted at rest, this is to make data extraction by an attacker extremely unlikely if not impossible, keeping data secure is what you want because stealing your data is worse than stealing your phone, in BFU mode, you can't use your fingerprint if you've set it up, you need to use your PIN/Password (if you've set it up too, which should normally be the case), in AFU (after first unlock) that means your device has been unlocked once, in which state, data are no longer encrypted at rest and you can unlock it with your fingerprint.

If you want an option that can remotely erase data, this option is not available as far as I know, you can probably use Find My Device with a Google account for this with sandboxed google play.

Restarting the device after 18 hours if it has not been unlocked at least once within this time lapse is precisely intended for theft and loss, you can reduce this time to 10 min, again, the aim is to quickly put the device in BFU state.

Probably9857

[deleted] a lot of confusion here, stemming from the fact that the OP seems (or at least seemed in the beginning) to be more concerned with disincentivising theft of the physical device more than he is concerned with securing the data on it from the theives.

Who can say he is wrong? Maybe he doesn't trust his roommates, who are not hackers, but might very well like to steal his device and sell it.

In any case, that would be an unusual threat model, and not one that GrapheneOS or most other serious security projects would prioritize.

ErminioOttone

Probably9857 Yes that' was my point because if as I understood from the post there are no disincentives from phone stealing and blocking it as if it was a stone. I don't see the differences in terms of security of datas with a standard android phones like s23, recent oneplus and so on. At the end no matter what thieves will shutdown the phone and will need to factory reset the phone - so deleting everything - as in GOS. So my question or maybe what I wanted to see in videos or in some presentations is the security comparaison between GOS devices and random other phones like android or apple.

Xtreix

ErminioOttone I don't see the differences in terms of security of datas with a standard android phones like s23

You're missing a lot if you compare the security and privacy features only through theft and loss. Unlike the Samsung S23, GrapheneOS lets you auto-reboot, with the option of setting a time between 10 minutes and 72 hours.

Once again, the aim is to quickly put the device in BFU mode, which you don't seem to understand.

No software can prevent someone from stealing your device, you can try Find My Device or Wasted on F-Droid to wipe data remotely, but I wouldn't rely too much on the reliability of these third-party solutions.

If you're worried about theft, a possible but impractical solution is to use a secondary profile for outdoor use.

You can reread what GrapheneOS offers in terms of functionality, but at this point I think you've received enough good answers to your questions.

https://grapheneos.org/features
https://grapheneos.org/faq#encryption

de0u

ErminioOttone I don't see the differences in terms of security of datas with a standard android phones like s23, recent oneplus and so on. At the end no matter what thieves will shutdown the phone and will need to factory reset the phone - so deleting everything - as in GOS.

But there is another hazard possible in a theft scenario: can a thief access the data on the phone? Can the thief transfer money from bank accounts? Can the thief access your contacts and trick your family members into sending money? That could cost much more than the price of a replacement phone.

The Pixel hardware and GrapheneOS are designed to protect data against disclosure. If a thief steals a phone and can't access the data and wipes the phone, this is a success in terms of protecting the data against disclosure.

Blastoidea

It is also incorrect to believe hat a Samsung phone is equally secure when compared to a (not EOL) pixel, running GOS.

The two things are not the same.

[deleted]

Blastoidea they may not be equally secure but Samsung does a great job at securing their devices and in regards to this I have found an interesting 3 part article which I plan on reading very carefully when I get time

https://www.riscure.com/tee-security-samsung-teegris-part-1/

rufus

After reading all of this I do have a question.
If I do lock my phone through the 2sec. press power button menu. Is it in a save state like BFU or does this happen only after reboot?

spiral

rufus

No, that is not BFU.

Again, BFU = "Before First Unlock." A full reboot of the phone is required to put the phone into BFU state.

rufus

And another question:
What would be a usefull and recommended setting to protect my datas from thefts?

« Previous Page Next Page »