Broadcasting of identifiers of gos

Olaolaho

I was trying to find out on the net but I didn't got a lot wiser from it so I geuss here is better to get some things clear..

What needs to be disabled more in order to be very difficult for the grapheneos device to find in or over the air.. By sniffing or what ever other methods there are available for state actors?

Lett me explain I am trying to figure out how much our devices broadcast to the outside and what to do to avoid it.

I have my phone always on flight mode and only connected to WiFi with a VPN..

Flightmode ON
Bleuthooth OFF
Emergency sos and wireless alert OFF
Printer OFF

What Is visible with this set up if any and what can be done more to lock down the device?

de0u

Olaolaho Maybe start here and read for a while? https://grapheneos.org/faq#cellular-tracking

jarell

See https://grapheneos.org/faq#default-connections for a detailed list of the network connections GrapheneOS makes.

gos208197

Make sure your phone doesn't have any hidden Wi-Fi networks saved as that will result in your phone constantly sending broadcasts for those hidden networks. That will form a unique fingerprint, as described in https://grapheneos.org/usage#wifi-privacy-scanning and https://discuss.grapheneos.org/d/2530-how-bad-is-it-to-use-hidden-wifi.

See these links for more analysis about GrapheneOS devices with airplane mode on, Bluetooth disabled, and Wi-Fi disabled:

The current guess (still to be confirmed) is that there may be Bluetooth leaks during boot even when Bluetooth is disabled.

If you're concerned about close proximity attacks, you should disable NFC. Wireless charging is another issue for close proximity attacks. It's not currently possible to disable wireless charging, so a local attacker can interact with a device via wireless charging. See https://discuss.grapheneos.org/d/22285-wireless-charging-privacy-and-security-risks and https://github.com/GrapheneOS/os-issue-tracker/issues/3271. I know little about wireless charging, but unique identifiers might be involved.

This may be beyond the details you're looking for, but a local attacker could also disassemble your phone to determine various identifiers or collude with emergency services via an emergency call to determine IMEI without disassembly.

You're basically already doing the best you can do if you always maintain the settings you've described.

Olaolaho

Thanks for clearing a few things but Lett me say a bit different..

Letts say I am a journalist and I have a meet with somebody in a other country who I need to protect being exposed. Let's say evil state actors are aware I have a inside informer and what to know who it is so they are full on me.

Letts say i have my regular phones with me only grapheneos devices 1 for work with only e2e apps and other for the normal life.. I take my flight settle in place and travel by bike foot step to make sure I don't have them on me when I meet.. At this point normally before grapheneos I would have the phones in a Faraday bag to be 100% sure it not ammits anything to trace me.. At any point I would need to connect to the net I have a mobile router with VPN installed what I only connect as a repeater from existing WiFi networks.. Does my device can be visible anywhere or anyhow if I have fliggtmode and only connected to my mobile hotspot without sim?

I read about WiFi scanning and the worrie about Bluetooth emitting at boot but is there a way to trace me (NOT BY PROXIMITY) just by having the phone on? Does the router can be the weak point?

Maybe its Hollywood thinking but are they capable to putt some identifiers from my phone or mobile router in some kind of system to scan the country or the city to know where it emits?

gos208197

Olaolaho At this point normally before grapheneos I would have the phones in a Faraday bag to be 100% sure it not ammits anything to trace me..

Faraday bags are not strictly required with GrapheneOS if you use airplane mode and disable unused radios (such as Bluetooth), but Faraday bags can provide peace of mind.

Olaolaho At any point I would need to connect to the net I have a mobile router with VPN installed what I only connect as a repeater from existing WiFi networks.. Does my device can be visible anywhere or anyhow if I have fliggtmode and only connected to my mobile hotspot without sim?

With this setup, the GrapheneOS device is not directly visible to eavesdroppers. When you connect to the mobile router using Wi-Fi (with the default per-connection randomized MAC setting), eavesdroppers can only see that some device is connected. Each reconnection to the router will look like a different device over the air (especially if an encrypted Wi-Fi mode is used such as WPA3). On the other hand, your mobile router is fully visible to the cellular network and cellular carriers. If that mobile router or the cellular plan is linked to your identity, your location - while the router is connected to cellular networks - will be collected and stored by cellular carriers.

Olaolaho I read about WiFi scanning and the worrie about Bluetooth emitting at boot but is there a way to trace me (NOT BY PROXIMITY) just by having the phone on? Does the router can be the weak point?

The router is definitely a weak point due to cellular tracking. By design, cellular networks collect precise locations of all connected clients. If your mobile plan or router's IMEI are connected to your identity, that location tracking is also linked to your identity.

Olaolaho Does your phone search for wifi networks when WiFi is on and does he sends out specific identifiers?

Read https://grapheneos.org/usage#wifi-privacy-scanning. If you have hidden Wi-Fi networks saved to your phone, that's bad for privacy. Hidden networks don't broadcast themselves, so instead the phone must constantly broadcast packets asking, "Is network ABC in proximity? Is network DEF in proximity?" The set of hidden networks that your phone broadcasts creates a unique fingerprint. If you have zero hidden networks saved, your phone cannot be uniquely identified during Wi-Fi scanning. Wi-Fi scanning only uses temporary, randomized identifiers.

Olaolaho I mean if I am today in Rome for example and tomorrow I be in Paris is my phone recognizable by this set up if I am personal tageted?

Your phone is not recognizable, but your mobile router is. It's trivial for the cellular network to determine the same person (possibly linked to your real identity) was in Rome and then in Paris based on your mobile router's IMEI and your cellular plan.

Note that if you've used that mobile router or cellular plan in a sensitive location (such as your home), it is effectively linked to your identity. The cellular carriers would have already stored the fact that your mobile router and/or cellular plan were connected while at your home in that example. And the location of your home (or workplace, hotel, etc.) may be linked to your identity through various methods.

Olaolaho

Does your phone search for wifi networks when WiFi is on and does he sends out specific identifiers?

I mean if I am today in Rome for example and tomorrow I be in Paris is my phone recognizable by this set up if I am personal tageted?

Olaolaho

gos208197 The router is definitely a weak point due to cellular tracking. By design, cellular networks collect precise locations of all connected clients. If your mobile plan or router's IMEI are connected to your identity, that location tracking is also linked to your identity.

Olaolaho Does your phone search for wifi networks when WiFi is on and does he sends out specific identifiers?

Read https://grapheneos.org/usage#wifi-privacy-scanning. If you have hidden Wi-Fi networks saved to your phone, that's bad for privacy. Hidden networks don't broadcast themselves, so instead the phone must constantly broadcast packets asking, "Is network ABC in proximity? Is network DEF in proximity?" The set of hidden networks that your phone broadcasts creates a unique fingerprint. If you have zero hidden networks saved, your phone cannot be uniquely identified during Wi-Fi scanning. Wi-Fi scanning only uses temporary, randomized identifiers.

Olaolaho I mean if I am today in Rome for example and tomorrow I be in Paris is my phone recognizable by this set up if I am personal tageted?

Your phone is not recognizable, but your mobile router is. It's trivial for the cellular network to determine the same person (possibly linked to your real identity) was in Rome and then in Paris based on your mobile router's IMEI and your cellular plan.

Note that if you've used that mobile router or cellular plan in a sensitive location (such as your home), it is effectively linked to your identity. The cellular carriers would have already stored the fact that your mobile router and/or cellular plan were connected while at your home in that example. And the location of your home (or workplace, hotel, etc.) may be linked to your identity through various methods.

Thank you for the very clear explaining. One detail I left it out of the explanation but what does all this change when the router not have any sim in it just use the repeater option from other WiFi networks? Ofcoursr the router has VPN with killswitch..

Upstate1618

Turn on airplane mode
Turn off Bluetooth
Turn off Wifi
Turn off Location
Turn off nfc
Turn off uwb

gos208197

If a SIM is removed from a cellular modem, which could be a mobile router or mobile phone, the device can still be tracked by the cellular network depending if flight mode is still disabled.

Removing a SIM card on its own does not avoid cellular network tracking. A cellular modem without a SIM card still communicates with the cellular network if flight mode is off. It does this for a variety of reasons. It's typical for cellular modems to determine the local time zone or local time from a cellular network, regardless if a SIM card is present.

When the SIM card is removed, identifiers specific to the SIM card are not included in those communications. That doesn't matter since the device has its own permanent identifiers (such as IMEI) that will be visible to the cellular network.

The proper way to turn off cellular tracking is to enable flight mode. If flight mode is enabled, cellular tracking is disabled regardless if a physical SIM card is installed (or if an eSIM is enabled). This assumes flight mode is properly implemented on your device. Hopefully that is the case for your mobile router. Flight mode works properly on Google Pixel devices.

If you want to use the mobile router as a Wi-Fi repeater and avoid tracking from Wi-Fi eavesdroppers, it would be ideal to randomize the MAC address identifiers the mobile router uses. The router will broadcast a MAC address when connecting to another Wi-Fi network. Additionally, the mobile router will broadcast a MAC address for its own hotspot that it provides for your phone to connect to. Someone who is in close proximity to your router can see those MAC addresses with a Wi-Fi packet sniffer software such as Kismet. Depending on your tracking concerns, someone could determine the same MAC address was in multiple locations. This could be done by someone in close proximity or by someone using Wi-Fi data sets like https://wigle.net.

Both of those MAC addresses should ideally be randomized between each connection to other networks and between each restart of the hotspot. If it's not possible to randomize the MAC addresses that frequently, you should change the MAC address any time you switch physical locations. For example, different MAC addresses should be used when in Rome versus when in Paris.

What's the benefit to using a router as a Wi-Fi bridge for a GrapheneOS device to connect to? Are you trying to share a single VPN connection across multiple devices? If you're trying to improve privacy and security, it's better to just connect directly to the other Wi-Fi network, without a mobile router in the middle, using GrapheneOS with an always-on VPN. GrapheneOS devices implement strong Wi-Fi privacy settings that look like a regular Android device to passive Wi-Fi eavesdroppers and to the Wi-Fi access points you connect to: https://grapheneos.org/usage#wifi-privacy. GrapheneOS also has much stronger, more recent security updates than many other devices such as routers.

What benefit does the mobile router provide, regardless if you use it as a cellular hotspot or as a Wi-Fi repeater? Can your GrapheneOS device be used directly without the router for your use case?