Pixel 9 pro fold integrity question

BraveDuck

I recently sent my friend a brand new pixel 9 pro fold in the mail with express post, the phone is brand new I opened the box though stock Android is on it. We are having an argument over opsec, they wanted me to put a PW on it and send it. Where I said it is irrelevant. Because when they flash GrapheneOS it will be completely new and can verify the integrity. Can this device still be tampered with in this scenario, in any way they are concerned that the bootloader is unlocked so can do anything. I disagree because once you install GrapheneOS it wipes the phone clean.

Any advice on this.

TrustExecutor

BraveDuck
You are 100% correct.
Nobody can tamper with it. Make them run a attestation with the Auditor app after they get it. If it gets attested OK the system is clean.

GrapheneOS

BraveDuck If you want to assure a higher level of security, you can make a pairing with them using the Auditor app in advance. If it has a password, someone can just wipe it and use it without one as a fresh install so that's not going to help. They should factory reset the device via recovery when receiving it if they're concerned about someone messing with it. If Auditor is set up in advance, they should check it using that pairing prior to that factory reset.

BraveDuck

TrustExecutor awesome thank you. Is there any technical resources you can point me to. Does auditor verify hardware integrity and bootloader integrity?

Dumdum

BraveDuck
https://attestation.app/about

BraveDuck

Dumdum Thanks for the link, so if I am not mistaken it also verifies the integrity of the hardware and firmware?

Dumdum

BraveDuck
At least according to the link, its Verified Boot that verifies the firmware/operating system. Auditor simply checks and validates that everything is correct. Not sure about verifying hardware though, I'm not seeing anything that suggests the hardware is checked for tampering but I also have no idea if that's possible (or necessary beyond the verification of the OS itself) for Auditor to do.

GrapheneOS

Dumdum Auditor won't pass if it's not genuine hardware but it can't detect stuff like attaching extra hardware to the device. The secure element and SoC are paired but most components like the touchscreen aren't.

BraveDuck

Thanks for the response @GrapheneOS. The package was sent with express postage, it would be extremely unlikely that extra hardware could of been added in a 24 hour time frame. Also the pixel 9 pro fold would be harder to open and put back together compared to a slab phone.

But essentially with auditor you can verify the integrity of the OS and firmware. And the password wouldn't of helped.