GrapheneOS Phone IMEI Randomizer

SpiritualGull

If a custom GrapheneOS phone were to be developed, would the team explore adding the ability to randomize the IMEI and other hardware identifiers alongside the Wi-Fi and Bluetooth MAC address randomizer?

DeletedUser405

SpiritualGull
That could maybe be handled better by mobile carriers such as cape.co . Cape modifies more than just the IMEI; according to them:

users can get all of the IMSI, IMEI, and MAID rotations

Rand-Uzer

SpiritualGull

There is a fork of KaiOS that has a IMEI randomizer ... I believe it beleiveit is called GerdaOS

argante

The ability to change the IMEI is a good idea, but the IMEI randomizer is bad. If you had a constantly changing IMEI and the same SIM, you would light up in red. Instead, it should work like this, you have SIM_1 and IMEI_1, SIM_2 and IMEI_2 etc. and manually set the IMEI for the current SIM. The IMEI is not random and you need to know how it is assigned (manufacturers and regions). So you can give the IMEI assigned to iPhone or Samsung phones, but you need to know what you are doing and not assign the IMEI randomly. Otherwise you can even block your phone.

phone-company

argante Changing the IMEI is prohibited in most countries. Better not

argante

phone-company Yes, I know about that. That would be a risk for GOS. However, if an external application were made, there would be no risk. Such an application would be very useful. Even if someone uses airplane mode, it would still be good to change the IMEI from time to time. Another advantage is that you can pretend to be an iPhone and thus drastically reduce the attack vector.

Viewpoint0232

phone-company Changing the IMEI is prohibited in most countries.

Many countries also prohibit call recording, but GrapheneOS allows it and gives the responsibility to the users.

Some countries (I think Japan and S Korea at least) also don't allow turning off the camera shutter sound.

TrustExecutor

This is a very bad idea.

argante

TrustExecutor Why? It is illegal to change the IMEI, but not the ability to do so. You can find such programs and there is no problem with it.

Stan804

Honestly, I would love to see it implemented.

argante

IMEI allows you to determine the phone model, which allows for a targeted attack. This applies to high-risk individuals. Here are some examples of prefixes with phone model assignments:

iPhone 15      353001
iPhone 15 Pro  353002
Galaxy S23     351005
Pixel 7        352001
Pixel 8        352101

From this you can easily see that the first three digits are the manufacturer.

By changing the IMEI for Pixel on iPhone, such high-risk individuals can make it more difficult to attack their phone.

other8026

argante By changing the IMEI for Pixel on iPhone, such high-risk individuals can make it more difficult to attack their phone.

Can make them stand out more, which would be something someone who's being targeted would want to avoid.

other8026

Relevant thread about this topic: https://grapheneos.social/@GrapheneOS/113319956422621755

argante

other8026

To summarize:

1) IMEI randomization is a poor way to improve privacy and will draw attention to yourself in practice.
2) Dedicated Hotspot devices aren't good for privacy/security.
3) Use airplane mode + Wi-Fi with our default per-connection MAC randomization for better privacy.

I use the third option. I'm considering completely removing the cellular antenna from the phone. I don't fully trust the airplane mode. It can also be easily accidentally turned off.

argante

other8026 I agree with what you wrote, but this will only happen if you change the IMEI randomly, like the MAC in GOS (I wrote about it earlier). However, if you permanently change the IMEI for the SIM you use, you will not stand out in any way.

r134a

Not endorsing changing IMEI in any way, neither did i try the validity of the following;

But it seems one could technically change IMEI on pixels, given what's written there is accurate (again i didn't test this, saved it as bookmark).

https://discuss.privacyguides.net/t/pixel-tensor-chip-imei-modification-guide/26295

If what is written there is accurate, one could root the device temporarily for the sole purpose of changing the IMEI, it's stated there changes will persist after factory reset and bootloader lock. One could then reflash GrapheneOS and I believe IMEI should be changed, again given what's written there is correct.

If one had a spare device, and is in a jurisdiction legally allowed to test this for educational/research purposes, with understanding what they are doing, i'm actually curios to the result specifically after reflashing GrapheneOS.

phone-company

Viewpoint0232 but the Imei is listed in network….. so your Phone can be blacklisted or redlisted or whatever 🤷

NetRunner88

Something like BlueMerle you can find on GLinet pocket routers is OK IMHO.
Anything else is useless.

(I am not commercially affiliated with glinet I just write an example of implementation)

GrapheneOS

NetRunner88 This makes you heavily stand out from regular phone users and you can be fairly easily tracked based on that due to how few people are using that setup.

NetRunner88

Rand-Uzer
It is garbage, plain garbage, i went this route before buying a Mudi

argante

NetRunner88 In my opinion it is worth modifying BlueMerle a bit. Generated IMEI should be saved and used with specific SIMs. It cannot be random IMEI every time.

NetRunner88

argante

Sure ! This makes sense