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Enhancing User Privacy on Android Devices. Name: Quang Do Supervisor: Raymond Choo Associate Supervisor: Ben Martini. Bachelor of Computer Science (Honours). Overview. Motivation Background Research Questions Literature Review Contributions RQ1: Permissions Removal
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Enhancing User Privacy on Android Devices Name: Quang DoSupervisor: Raymond Choo Associate Supervisor: Ben Martini Bachelor of Computer Science (Honours)
Overview • Motivation • Background • Research Questions • Literature Review • Contributions • RQ1: Permissions Removal • RQ2: Storage Control • Conclusions • References
Motivation (1/2) • Smartphones are becoming more and more common • They are being used for more than just phone calls • Online Shopping • Banking • Medical Records • Tasks performedby “apps”. http://au.businessinsider.com/another-record-quarter-for-smartphone-sales-2013-55
Motivation (2/2) • More sensitive information stored within the devices. • If compromised, could put user or even corporations at risk. • Banking statements • User logins and passwords • Text messages • Android has 79.3% of the global smartphone market share (http://www.businesswire.com/news/home/20130807005280/en/Apple-Cedes-Market-Share-Smartphone-Operating-System) • Google Play Store: 1 000 000+ apps (http://www.phonearena.com/news/Androids-Google-Play-beats-App-Store-with-over-1-million-apps-now-officially-largest_id45680)
Background • Google Android • Released in September 2008 • Apps (APK File) • Request permissions • Internet, Contacts Data, Messages, etc. • Defined within a manifest XML file contained within an app’s installation package. • Apps can only be granted all their requested permissions • No current method to deny resource access
Research Questions • Research Question 1 (RQ1): • How effective is permissions removal in enhancing user privacy on Android devices? • Research Question 2 (RQ2): • How effective is storage permissions in enhancing user privacy on Android devices?
Literature Review • Android OS Changes • Categorise permissions (Felt et al., 2012) • Fine-Grained App Control • Deny or allow a resource request as it occurs (Kern & Sametinger, 2012) • Generally requires OS changes • Mock/Shadow Data • Send faked data to apps • Mock location (MockDroid - Beresford et al., 2011) • Permissions Removal • No OS modifications required
RQ1: Permissions Removal (1/4) • General Process: • Decompile App • Remove Permissions • Recompile App
RQ1: Permissions Removal (2/4) • Methodology • Select Social Networking Apps • Select Permissions to remove • Perform Permissions Removal (From previous slide) • Test for errors • Selecting Permissions • Vital to functions • Harmfulness • Feasible to remove
RQ1: Permissions Removal (3/4) • Permissions to Remove: • Read contacts • One of the most requested • Access fine location • Should not be required • Apps have been found to leak location information (Zhou et al., 2011)
RQ1: Permissions Removal (4/4) • Results • Access to location can be removed simply • Access to contacts data cannot be removed easily • Paper has been accepted by the 47th Hawaii International Conference on System Sciences (HICSS) (ERA A Rank conference) • Limitations • Key signing issues • Manual removal • Manual error checking • Difficult to debug/code
RQ2: Storage Permissions (1/2) • All apps are given access to non-protected storage locations. • Security risk • User documents, photos, downloads readable by all apps. • Apps with write access can also write to all non-protected storage. • Proposed Solution: • Use Unix access rights/permissions to control access to storage folders. • Design an app to help enforce and control these settings.
RQ2: Storage Permissions (2/2) • Findings: • Android External Storage • Android defaults external storage to FAT32 file system • FAT32 does not have Linux file permissions • The external storage needs to be formatted to ext4 (Using root) • Android Users • Each Android app is given a user ID • Android hardcodes user groups • Current Results • Folders can be restricted so that only one app can read or write to them.
Conclusions • Android permissions removal is a viable method of improving user privacy, but requires more automation. • The Android operating system itself needs to have finer grained control over what each permission allows. • Android user groups is very limited and hardcoded.
References • A.P. Felt, E. Ha, S. Egelman, A. Haney, E. Chin & D. Wagner, “Android permissions: User attention, comprehension, and behavior”, SOUPS 2012, p. 3 • M. Kern, & J. Sametinger, “Permission Tracking in Android”, UBICOMM 2012, pp. 148-155. • AR. Beresford, A. Rice, N. Skehin & R. Sohan, “MockDroid: trading privacy for application functionality on smartphones”, HotMobile 2011, pp. 49-54. • Y. Zhou, X. Zhang, X. Jiang & V. Freeh, “Taming information-stealing smartphone applications (on Android)”, TRUST 2011, pp. 93-107.