Determination and Enforcement of Least-Privilege Architecture in Android

Modern mobile platforms rely on a permission model to guard the system's resources and apps. In Android, since the permissions are granted at the granularity of apps, and all components belonging to an app inherit those permissions, an app's components are typically over-privileged, i.e., components are granted more privileges than they need to complete their tasks. Systematic violation of least-privilege principle in Android has shown to be the root cause of many security vulnerabilities. To mitigate this issue, we have developed DELDROID, an automated system for determination of least privilege architecture in Android and its enforcement at runtime. A key contribution of our approach is the ability to limit the privileges granted to apps without the need to modify them. DELDROID utilizes static program analysis techniques to extract the exact privileges each component needs for providing its functionality. A Multiple-Domain Matrix representation of the system's architecture is then used to automatically analyze the security posture of the system and derive its least-privilege architecture. Our experiments on hundreds of real world apps corroborate DELDROID's ability in effectively establishing the least-privilege architecture and its benefits in alleviating the security threats.