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I am planning to use a smartphone as a media player and maybe to read the occasional ebook or pdf.

If I were to turn off all connectivity, e.g., bluetooth, wifi, gps, then remove the sim card and/or put it in airplane mode, is there still a way the phone can be tracked? Is a phone with no sim card in or in airplane mode still visible to cell towers/IMSI catchers?

I'm aware that GPS receivers can only receive and do not send data. How does a smartphone use the GPS data received to track a user's location. I would like to know because after having turned off or disabled all unnecessary background apps, I found that I am unable to permanently force stop or disable some location and bluetooth apps that run in the background.

Would switching to something like LineageOS or Replicant (without reinstalling Play Store or any Google apps) help fix this? How free are OS' like these from Google's code/data-collecting?

If I were to use wifi with no other connectivity enabled and routed the internet traffic to tor through a transparent proxy, should that be enough for anonymous casual browsing?

  • Depending on the country, a phone without a SIM will connect to the mobile network for emergency calls only. (I think it doesn't in Germany and needs a SIM - or maybe it connects and is rejected.) – DetlevCM Aug 14 '18 at 9:04
  • @DetlevCM sure, but not in airplane mode – multithr3at3d Aug 14 '18 at 13:20
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    You could buy a cheap tablet without GPS or SIM card, and use it to browse. Easier to do, less moving parts, larger screen. – ThoriumBR Aug 14 '18 at 13:29
  • Anonymous browsing? NOT unless you install a good VPN services that force tunnel all the traffics to somewhere else. A cheapo VPN might leak your location through DNS leak. – mootmoot Aug 14 '18 at 15:53
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The answer will depend on the manufacturer, OS, hardware, and applications It is hard to give a complete answer and you can't control any of the previous 3 in a normal phone.

GSM protocol does not require a SIM card to be able to execute an emergency call. Any malicious application in the mobile can disclose your relative positioning using this strategy.

Another possibility, for example, is with Android OS, it uses the Google play store to provide accurate info to apps on positioning and other data.

Google play store or any app can be constantly collecting info on your phone about your wireless profile and surrounding networks.

Even if you are offline it can still track you by the GPS or the wireless SSID networks that are near you, and when online again synchronize the information. I would not trust much airplane mode as it is based on software and not hardware.

My way of being off the grid, I would buy a Raspberry Pi and a 7" touchscreen and install Linux with one of those power sources to recharge the phones you will have power for around 5 hours. If you need a network to connect USB WiFi, if you need GPS to connect USB GPS... if you require 3G then connect a USB 3G stick, etc... You own the OS so you can decide what you keep or allow to be collected.

Your tablet will not be small but it will work and keep you safer as you control almost everything...

  • Hugo, I've corrected grammar in your post however, unfortunately, I am still having issues understanding what you mean in certain places in your post, please could you iron out any issues after my edit to make the post more readable? Thank you. – J.J Aug 14 '18 at 9:46
  • Hi. Thanks for answering. Regarding the Play Store and Google tracking, will replacing Android with something like LineageOS or Replicant (without reinstalling Play Store or any Google apps) help mitigate the risk? – user942937 Aug 19 '18 at 6:17
  • I have tried playing around with a similar device as you have mentioned, but I can't manage to get more than a few hours out of it. – user942937 Aug 19 '18 at 6:18
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To answer your 4th question: If I were to use wifi with no other connectivity enabled and routed the internet traffic to tor through a transparent proxy, should that be enough for anonymous casual browsing?

In my opinion yes for most normal cases, off course if a backdoor is implanted (due to previously unsafe access), it will be game over from the start.

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