Byron Alleman
Will Galloway
Jesse McCall
Permission Based Security Model
 Users can only use features for which their permissions




grant them access
Abstracts the hierarchy system
More freedom than the hierarchy system
More secure in theory because nothing is trusted
unless they have permissions
Pretty much pioneered by Android
Android Permissions Overview
 Android treats all applications as untrustworthy users
 Each app runs in its own virtual machine
 If an application has special needs it must request
permission
 Attempting to access a system feature that the
application doesn’t have permission for either results
in the feature not starting or a security error
Android Permissions Continued…
 Requested permissions are displayed in the Play store
 Android assigns the application a unique linux user ID
 Permissions requested by an application are declared
in the application’s AndroidManifest.xml file
Pros
Cons
 Applications should only
 Applications can request
have access to features they
require to function as
intended
 Ideally applications wont be
able to negatively impact
other applications or the user
more permissions than they
require
 Leaves system open to
possible malicious attack
Types of Permissions
 Normal
 Low-risk permissions
 Automatically granted
 Example: Flashlight, Read SD card contents
 Dangerous
 Higher-risk permissions that the user must confirm
before installing the application
 Can negatively impact the user
 Example: Internet Access, Send SMS
Types of Permissions continued
 Signature
 Permissions that the system only grants if the requesting
application is signed with the same certificate as the
application that declared the permission.
 Automatically granted
 Signature/System
 Permissions that the system only grants to apps that are
in the Android system image or signed with the same
certificate
 Automatically granted
Application Defined Permissions
 Applications can enforce their own defined
permissions.
 Ensures self-protection and preservation of the
application.
 Applications can specify exactly what outside
applications can access of its resources.
The Problem
 Many users don’t understand the permissions system
 Many users ignore the permissions
 Permission descriptions aren’t always clear
 Permission location can easily be overlooked in the
Play store
Survey Results
 51.9% of surveyed always read permissions before
downloading an app
 44.3% of surveyed feel that all permissions are easy to
comprehend
 78.2% of surveyed have decided not to install an app
based on its permissions
How to Fix
 Educate users about permissions and their impact
 Locate potentially hazardous applications on the
device
 Better layout for permissions on the Play Store
 Advise users to be cautious when downloading from
the third party app stores (like Amazon Market)
Other Applications
 Pocket Permissions
 App Profiles
 DroidRanger
 Stowaway
Our App
 Lists all permissions used by apps, grouped by apps
 Lists all apps that use each permission
 List apps that have a high risk based on permissions
 User guide to permissions
 Explains permissions
 Show the risk of each permission
 Tips for Android safety
DEMO
QUESTIONS?