Used phones provide hackers with personal photos, emails and more

Second hand phones contain a vast quantity of personal information that is still accessible, according to a study by security firm, Avast.

Avast bought 20 smartphones on eBay that had been "wiped," but were still able to access 40,000 photos, 750 emails and texts, 250 names and addresses, a completed loan application and more. One of the phones did have security software installed, but even this provided sensitive information.

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On one particular handset, hackers at Avast were able to access the previous owner's Facebook page, see his GPS coordinates and find the names and numbers of over a dozen contacts.

The issue of phone security is one that needs to be taken more seriously, according to a recent report. A Consumer Reports study found that only 14 per cent of Americans have antivirus software on their phones and only 8 per cent installed software that could erase their phone's data remotely.

The main problem is that when a file is deleted the operating system simply deletes links to that file and marks the space as available. However, until that particular file is overwritten, it can still be recovered.

"Selling your used phone is a good way to make a little extra money, but it's a bad way to protect your privacy," said Jude McColgan president of mobile at Avast.

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Avast's free software makes the file irretrievable as soon as it's deleted and other security brands, such as McAfee and Symantec have similar packages available.

It has become increasingly common for PCs at home and work to come preloaded with antivirus software, meaning security can often be taken for granted. However, as the recent Avast study shows, consumers might want to think twice before selling their old smartphone.