Sold a smartphone? Beware, your data can still be accessible

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Are you planning to junk your smartphone in the second-hand device market for the sake of a new one? Beware as your data can be retrieved from your old phone.

A new Cambridge study has found that user data is retrievable from second-hand Android devices that have been wiped via a factory reset, techweekeurope.co.uk reported. Such data can be recovered even from handsets protected by full-disk encryption, the researchers said.

Most Android handsets offer no easily accessible way of deleting user data, including access tokens, messages, images and other content, the study said.

Experts have been airing their concerns for some time now that the smartphones are extraordinarily difficult to clear of user data.

The study examined 21 second-hand devices running Android versions from five manufacturers that had been wiped using the operating system's built-in factory reset feature.

But the problems also exist with third-party data deletion applications, such as those offered by antivirus vendors, the researchers said.

The team was able to recover data including multimedia files and login credentials from wiped phones, and many of the handsets yielded the master token used to access Google account data, such as Gmail and Google Calendar.

The problem results from multiple issues, including the inherent difficulty of fully deleting data from the flash memory used in smartphones, something due to the physical nature of such memory chips, according to the research.

Other issues include vendors' failure to include necessary drivers or failures introduced by their modifications of Android for individual devices.

As a proof-of-concept, the researchers recovered the master token in a device and found that after reboot, it successfully re-synchronised contacts, emails and other data.

The master token, used to access Google accounts, was found to be retrievable in 80% of the devices that had a flawed factory reset mechanism.

Devices protected with encryption can still be accessed, because the file storing the decryption key is not erased, making it accessible to cracking, the study said.

This is problematic specially for those who shop using mobile.

^ these smartfone OS these days are practically violation of all personal and privacy rules. they absolutely don't give user any authority over their own fone. instead all user data as well as user's contacts data are synced to the service provider servers. even if one can think he has deleted all his personal data, at least some of those still remain somewhere at least by some means accessible to someone.

Looks like we need to feed our old smarties into the grinder.

I was preparing to write something along the line, "It's a known fact that Factory Reset doesn't wipe data, and that's why it's important to overwrite junk values to them maybe repeatedly." But, then I read the article and especially the last line,

Devices protected with encryption can still be accessed, because the file storing the decryption key is not erased, making it accessible to cracking, the study said.

Oh dear. Never thought about that. So far I haven't sold any smartphone. They get real old really soon. So didn't find a need to sell them anyway. But now even I could, I probably should just recycle it!

R

I don't think the technique is available to public so nothing to worry. Data recovery is not a child play

I don't sell my phones. And along that it ain't that easy to recover the data.

^^ I kinda have to agree on that. Data from mobile isn't easy to recover. Especially if it's the Internal memory that we are talking about.

I once wiped the data from my Moto X when I forgot to take a backup before unlocking bootloader. I used this guide, had to install a bunch of apps like Busybox on my phone, setup Cygwin on PC, get Netcat and ADB. Finally had to use VHD tool (from obscure part of Internet) to fetch and convert the image of the Internal memory and then use Recuva to "attempt" the recovery.

Was I able to recover my lost photos? Nah. Even after spending hours and days I wasn't able to recover my own data.

Recovering from internal memory is too far stretched.
If you think that way, anything is possible. So either stop using tech or stop worrying.

dashing.sujay said:
Recovering from internal memory is too far stretched.
If you think that way, anything is possible. So either stop using tech or stop worrying.

Golden words

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Nothing is ever deleted in the digital world.