Security Analysis of Android Factory Resets

Laurent Simon, Ross Anderson

Research output: Contribution to conferencePaperpeer-review

Abstract / Description of output

With hundreds of millions of devices expected to be traded by 2018, flaws in smartphone sanitisation functions could be a serious problem. Trade press reports have already raised doubts about the effectiveness of Android “Factory Reset”, but this paper presents the first comprehensive study of the issue. We study the implementation of Factory Reset on 21 Android smartphones from 5 vendors running Android versions v2.3.x to v4.3. We estimate that up to 500 million devices may not properly sanitise their data partition where credentials and other sensitive data are stored, and up to 630M may not properly sanitise the internal SD card where multimedia files are generally saved. We found we could recover Google credentials on all devices presenting a flawed Factory Reset. Full-disk encryption has the potential to mitigate the problem, but we found that a flawed Factory Reset leaves behind enough data for the encryption key to be recovered. We discuss practical improvements for Google and vendors to mitigate these risks in the future.
Original languageEnglish
Number of pages10
Publication statusPublished - 21 May 2015
Event4th Mobile Security Technologies Workshop 2015 - San Jose, United States
Duration: 21 May 201521 May 2015
Conference number: 4


Workshop4th Mobile Security Technologies Workshop 2015
Abbreviated titleMoST 2015
Country/TerritoryUnited States
CitySan Jose
Internet address


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