Menu
Factory reset in Android phones leaves sensitive user data behind

Factory reset in Android phones leaves sensitive user data behind

Researchers recovered access credentials, emails, text messages and other sensitive information from wiped Android phones

Android apps

Android apps

It's common sense to reset an Android phone to its factory state before selling or disposing of it. But beware, researchers recently found that this often fails to properly wipe all sensitive user data from the device.

A test on 21 second-hand smartphones running Android versions between 2.3.x (Gingerbread) and 4.3 (Jelly Bean) revealed that it's possible to recover emails, text messages, Google access tokens and other sensitive data after the factory reset function had been used.

The study was done by researchers Laurent Simon and Ross Anderson from the University of Cambridge in the U.K. on used devices bought from eBay between January and May 2014. The devices included models from Samsung Electronics, HTC, LG Electronics, Motorola and three from Google's Nexus line of phones.

In 80 percent of cases the researchers managed to recover the Google master token that could allow an attacker to re-synchronize the device with the previous owner's Google account, gaining access to the emails, contacts, Wi-Fi passwords and other data backed up to that account.

In some cases they also recovered access tokens from apps such as Facebook, portions of emails, SMS messages and other instant messaging conversations.

"The reasons for failure are complex; new phones are generally better than old ones, and Google's own brand phones are better than the OEM offerings," Ross Anderson said in a blog post. "However the vendors need to do a fair bit of work, and users need to take a fair amount of care."

Encrypting the phone can help mitigate some of the risk, but not completely. The researchers found that in some cases an attacker could recover enough information after a factory reset operation to break the encryption key using brute-force techniques. In order to prevent this, it's essential for phone owners to set a strong password when encrypting their phones, as 4-digit PINs are easy to crack.

Based on their findings, the researchers estimate that up to 500 million devices may not properly erase the data partition where the OS and apps store credentials and up to 630 million may not sanitize the SD card where multimedia files such as photos and videos are typically saved.

In a separate study, the researchers analyzed anti-theft features like remote device locking and wiping offered by top mobile security apps. Their conclusion was that these apps do not represent an alternative to the flawed built-in factory reset, because they are limited by the OS architecture and APIs in what they can do.

The only viable solution would be improvements to the data wiping mechanism made by the phone vendors themselves, the researchers said.

It's not clear if the factory reset function has been improved in Android versions newer than 4.3.

Google did not immediately respond to a request for comment.


Follow Us

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags securityprivacyMotorolamobile securityGooglehtcdata protectionuniversity of cambridgeSamsung ElectronicsLG ElectronicsForensics

Featured

Slideshows

Meet the leading female front runners of the Kiwi channel

Meet the leading female front runners of the Kiwi channel

Reseller News honoured the leading female front runners of the New Zealand channel at the 2018 Women in ICT Awards (WIICTA) in Auckland. The awards honoured standout individuals across seven categories, spanning Entrepreneur; Innovation; Rising Star; Shining Star; Community; Technical and Achievement.

Meet the leading female front runners of the Kiwi channel
Meet the top performing customer-centric Microsoft channel partners

Meet the top performing customer-centric Microsoft channel partners

Microsoft honoured leading partners across the channel following a year of customer innovation and market growth in New Zealand. The 2018 Microsoft Partner Awards recognised excellence within the context of the end-user, spanning a host of emerging and established providers.

Meet the top performing customer-centric Microsoft channel partners
Reseller News launches new-look Awards at 2018 Judges’ Lunch

Reseller News launches new-look Awards at 2018 Judges’ Lunch

Introducing the Reseller News Innovation Awards, launched to the channel at the 2018 Judges’ Lunch in Auckland. With more than 70 judges now part of the voting panel, the new-look awards will reflect the changing dynamics of the channel, recognising excellence across customer value and innovation - spanning start-ups, partners, distributors and vendors.

Reseller News launches new-look Awards at 2018 Judges’ Lunch
Show Comments