Thought you could just give away or sell your old Android phones without worrying, did you? You thought wrong. CNet had a chat with security company Avast who said that the old go-to, factory reset, isn't the security safeguard we all thought it was.
Avast is mostly known for its free security software that runs on PCs and Android. The company did an experiment which involved buying 20 used Android smartphones from eBay and seeing how much they could recover. Quite a lot, actually. Avast employees found over 40,000 photos that included 250 nude male selfies, contacts, emails and text messages, the identities of previous phone owners. The jewel of the lot? A completed loan application.
Deleted data could still haunt you
Basically we have been misled about what a factory reinstall actually does. It does not actually wipe all data but phones are only cleaned at the application layer. This means data could still be lying around on the phone, waiting to be mined by anyone with some skill.
Even more disturbing? Avast did not need super hacking skills but generic, publicly available software like FTK Imager. Though the phones appeared to be thoroughly cleansed of data, a little bit of digging retrieved old messages and other private data.
Of course Avast had to mention that its own security app did have a handy deletion tool that really did get rid of more data than a 'factory reset'.
If you don't want to download yet another app, why not just use Android's own encryption feature that you can access in settings. It will encode your data and slap passcode protection.