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I'm using a Xiaomi Redmi 3 device with latest MIUI 8 Global Dev Rom (Android 6 based with weekly updates). I'm only using Fingerprint Unlock and my device is not fully encrypted.

I'm wondering how hard it is for an attacker in case my phone is lost to access the internal memory. The external SDcard can be easily removed but is it easy to access the internal one?

I have not opened up the Xiaomi Bootloader, hence the theft could not simply flash another Rom to get access to the device. Also no USB Debugging / Developers options enabled. So in case he connects the device to a USB port; IMO there should be no way to get access to the internal memory, right? (a friend of mine broke the display of his iphone and not even the Applstore could help him get access to his DCIM folder to copy his non-backupped images; hence I hope this kind of security is also provided by the latest Android OS).

The only way I could currently think of would be to open up the device, somehow solder the memory ASIC to remove it from the platine and get access. As Im not talking about super safety-relevant data stored on my internal memory, this scenario will not come true for a random theft and is not in my focus asking this question.

Thanks in advance

  • Perhaps this helps – Purefan Mar 16 '17 at 9:05
  • @Purefan Not sure how a page saying "Who is vulnerable to fishing?" and advertising some sort of fishing simulator can be deemed helpful. If anything, it looks spammy. – Dmitry Grigoryev Mar 16 '17 at 10:39
  • @DmitryGrigoryev I think you got the link wrong, my link goes to infosecinstitute.com and ctrl+f doesnt find "who is vuln". If you scroll down it goes into explaining how to modify values in memory for a game which I think is related to the question here posted – Purefan Mar 16 '17 at 11:49
  • @Purefan: Good link, though my device is neither rooted nor has got an open bootloader. Developer options are disabled. Hence, apart from some sort of unpatched OS vulnerables; I'm still not sure whether it is possible to access the memory. – tim Mar 16 '17 at 12:02
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    @Dmitry: There was a button "no thanks" (lower button) on the right hand side -> Click to get to the article – tim Mar 16 '17 at 12:09
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Reading unencrypted internal flash IC is a job that can be done for under $100. Last time I have checked, universal flash programmers were sold on e-bay for $30 to $300. If anything leads the thief to believe that your data is more valuable than your phone, this will be done.

If the thief is after your phone, they will have little incentive looking at your data. They will try to either unlock or reflash your phone to make it usable, whichever is easier. This may not be possible via external interfaces, but certanly doable if someone is willing to open the device: after all, those phones are flashed at the production line, so there is a way to do it.

Bottom line, you have to use encryption if you need to keep your data private. If that data is also valuable, you should use a more secure authentication method than a fingerprint.

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Contrary to iOS, that uses full disk encryption by default, only android devices with android 6.0 and above that have 50MiB-per-second internal memory speed, are configured to use disk encryption by default (source). I assume that there are probably exception to this rule (but whatever).

So any other android phone is likely to have no encryption by default. I assume your phone doesn't have disk encryption turned on because you say you are hoping it is by default.

I don't know why you assume that physically removing the memory and reading it is so inconceivable, I believe it shouldn't be that difficult. But to answer your question:

A quick google search revealed some tools that claim to rescue data from a locked phone and some methods that use ADB to remove the device password. This is probably version dependent, and has some more specifics that determine whether this is possible or not so there cannot be a single answer to this question. But certainly, the answer is either yes - your data can be extracted or maybe - depending on version and configuration.

  • Thanks for your input. I thought ADB would only work in case developer options are activated, but maybe Im wrong. I assume your phone doesn't have disk encryption turned on because you say you are hoping it is by default. => I do not hope it is on by default, I know it is off with my device :) But maybe it'd be a good idea to turn it on. – tim Mar 16 '17 at 12:06

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