Wiping' Android Cellphones May Not Really Get Rid of Data

What's the most embarrassing information you've captured, then deleted, on your phone? Before you sell it and move on to the next version, know this: your blush-inducing selfies may live on even if you try to "wipe" your phone.

The software security gurus at Avast discovered thousands of photos and files of personal information on 20 phones that were sold to them as 'wiped clean.' (Image source: Avast).

Avast, a Prague-based security software firm, just proved that using the "factory reset" and "delete-all" functions on some phones will not purge embarrassing photos or personal information. They purchased 20 phones from unsuspecting previous owners and found a treasure trove of data on the phones that were supposedly wiped clean.

"(One) guy was really into anime porn,” Caroline James, PR manager for Avast, said. Hackers at Avast were able to identify the previous cell phone's owner, access his Facebook page, track his previous whereabouts through GPS coordinates, and find the names and numbers of more than a dozen of his closest contacts, according to Venture Beat. The company able to discover this man's fetish and, perhaps what was a preventative measure, a completed copy of his Sexual Harassment course.

According to the Daily Mail, Avast found the information below on just 20 phones that previous owners thought were wiped clean:

• More than 40,000 stored photos

• More than 1,500 family photos of children

• More than 750 photos of women in various stages of undress

• More than 250 selfies of what appear to be the previous owner's manhood

• More than 1,000 Google searches

• More than 750 emails and text messages

• More than 250 contact names and email addresses

• Four previous owners’ identities

• One completed loan application

Google responded to Avast's research by saying the tests were conducted on "older" phones.

"This research looks to be based on old devices and versions (pre-Android 3.0) and does not reflect the security protections in Android versions that are used by the vast majority of users," Google told the Daily Mail. "If you sell or dispose of your device, we recommend you enable encryption on your device and apply a factory reset beforehand; this has been available on Android for over three years."

Only one of the phones had security software loaded on it, but that phone gave up some of the most sensitive information. And according to a recent Consumer Reports study, only 14 percent of Americans installed anti-virus software on their phone, and only eight percent use software that could erase their phone remotely.

Avast points out, factory resets aren’t as thorough as most users think they are. That’s because when you delete a file, it isn't really gone.

Operating systems don't purge information when a delete command is given; they simply remove the pointers to that file and classifies the space that the file occupies as available for overwrite. But until that space is overwritten with new information, the 'deleted' file can be restored.

And yes, your computer hard drive works in the same way.

Check out Avast's video on their data-mining test, here:

(H/T: Daily Mail)

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Follow Elizabeth Kreft (@elizabethakreft) on Twitter. 

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