Looks like a bad news for phone users who want to sell their devices as new research shows that their personal data can still be retrieved after factory reset.
Google's popular mobile operating system Android's factory reset is apparently not as effective as users perceived it to be, a team of Cambridge University researchers have affirmed.
According to the group, nearly 500 to 630 million Android devices might be incapable of completely wiping the data saved in their internal disk and SD cards. The team tested 21 devices running Android 2.3 to 4.3 from five different phone makers that already went through the factory reset.
Despite the fact that the data stored in each sample device was protected with full-disk encryption, the team was able to recover at least part of the data stored in each sample device, according to reports on Engadget.
Data such as contacts, images, videos, texts, emails and also log-ins for third party apps such as WhatsApp and Facebook were recovered. They were also able to retrieve the master token needed to access all Google user data in 80 percent of the phones.
There are several possible reasons for reset failure, according to the researchers, such as manufacturers sometimes not loading a phone's software with the drivers needed to completely wipe its internal disk or SD card add-on. Flash drives are notably difficult to erase.
In addition, the problem could arise due to multiple issues including the deep-rooted difficulty of completely deleting data from the flash memory used in smartphones, something due to the physical nature of such memory chips, according to the research.
Other issues include vendors' failure to include necessary drivers or failures due to the physical nature of memory chips, according to the research. Vendor's failure to incorporate crucial drivers is yet another issue along with failures introduced by their modifications of Android for individual devices, according to Hindustan Times.
The group successfully recovered the master token in a device and found that after reboot, it re-synchronized data including contacts and emails. The study further revealed that devices such as phones which are protected with encryption can still be accessed even after factory reset.
Whether Google or any other phone manufacturers whose devices were tested are doing anything about this issue, is still not clear.
