Biblio

Mobile applications frequently request sensitive data. While prior work has focused on analyzing sensitive-data uses originating from well-dened API calls in the system, the security and privacy implications of inputs requested via application user interfaces have been widely unexplored. In this paper, our goal is to understand the broad implications of such requests in terms of the type of sensitive data being requested by applications.

To this end, we propose UiRef (User Input REsolution Framework), an automated approach for resolving the semantics of user inputs requested by mobile applications. UiRef’s design includes a number of novel techniques for extracting and resolving user interface labels and addressing ambiguity in semantics, resulting in signicant improvements over prior work.We apply UiRef to 50,162 Android applications from Google Play and use outlier analysis to triage applications with questionable input requests. We identify concerning developer practices, including insecure exposure of account passwords and non-consensual input disclosures to third parties. These ndings demonstrate the importance of user-input semantics when protecting end users.

Security isolation is a foundation of computing systems that enables resilience to different forms of attacks. This article seeks to understand existing security isolation techniques by systematically classifying different approaches and analyzing their properties. We provide a hierarchical classification structure for grouping different security  isolation techniques.  At the top level, we consider two principal aspects: mechanism and policy. Each aspect is broken down into salient dimensions that describe key properties. We break the mechanism into two dimensions: enforcement location and isolation granularity, and break the policy aspect  down into three dimensions: policy generation, policy configurability, and policy lifetime. We apply our classification to a set of representative papers that cover a breadth of security isolation techniques and discuss trade-offs among different design choices and limitations of existing  approaches.

Smartphone users often use private and enterprise data with untrusted third party applications.  The fundamental lack of secrecy guarantees in smartphone OSes, such as Android, exposes this data to the risk of unauthorized exfiltration.  A natural solution is the integration of secrecy guarantees into the OS.  In this paper, we describe the challenges for decentralized information flow control (DIFC) enforcement on Android.  We propose context-sensitive DIFC enforcement via lazy polyinstantiation and practical and secure network export through domain declassification.  Our DIFC system, Weir, is backwards compatible by design, and incurs less than 4 ms overhead for component startup.  With Weir,  we demonstrate practical and secure DIFC enforcement on Android.