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 New Zealand Reseller News newsletter!

Error: Please check your email address.

Tags Motorolauniversity of cambridgeLG Electronicssecuritymobile securitySamsung ElectronicsForensicsdata protectionprivacyhtcGoogle

Slideshows

Top 50 defining moments of the New Zealand channel in 2016

Top 50 defining moments of the New Zealand channel in 2016

Reseller News looks back on a tumultuous 12 months for the New Zealand channel, assessing the fallout from a year of sizeable industry change. Whether it be local or global mergers and acquisitions, distribution deals or job changes, the channel that started the year differs somewhat to the one set to finish it - Reseller News assesses the key moments that made 2016.​

Top 50 defining moments of the New Zealand channel in 2016
​Hewlett Packard Enterprise honours high achieving NZ channel

​Hewlett Packard Enterprise honours high achieving NZ channel

Hewlett Packard Enterprise honoured its top performing Kiwi partners at the second running of its HPE Partner Awards in New Zealand, held at a glitzy ceremony in Auckland. Recognising excellence across eight categories - from distributors to resellers - the tech giant celebrated its first year as a standalone company, following its official split from HP in 2015.

​Hewlett Packard Enterprise honours high achieving NZ channel
Nutanix treats channel partners to Christmas cruise

Nutanix treats channel partners to Christmas cruise

Nutanix recently took to the seas for a Christmas Cruise around Sydney Harbour with its Australia and New Zealand staff, customers and partners to celebrate a stellar year for the vendor. With the sun out, they were all smiles and mingled over drinks and food.

Nutanix treats channel partners to Christmas cruise
Show Comments