ClickPattern: A Pattern Lock System Resilient to Smudge and Side-channel Attacks

Pattern lock is a very popular mechanism to secure authenticated access to mobile terminals; this is mainly due to its ease of use and the fact that muscle memory endows it with an extreme memorability. Nonetheless, pattern lock is also very vulnerable to smudge and side channels attacks, thus its actual level of security has been often considered insufficient. In this paper we describe a mechanism that enhances pattern lock security with resilience to smudge and side channel attacks, maintains a comparable level of memorability and provides ease of use that is still comparable with Pattern Lock while outperforming other schemes proposed in the literature. To prove our claim, we have performed a usability test with 51 volunteers and we have compared our results with the other schemes

SYSTEMATIC DISCOVERY OF ANDROID CUSTOMIZATION HAZARDS

The open nature of Android ecosystem has naturally laid the foundation for a highly fragmented operating system. In fact, the official AOSP versions have been aggressively customized into thousands of system images by everyone in the customization chain, such as device manufacturers, vendors, carriers, etc. If not well thought-out, the customization process could result in serious security problems. This dissertation performs a systematic investigation of Android customization’ inconsistencies with regards to security aspects at various Android layers. It brings to light new vulnerabilities, never investigated before, caused by the under-regulated and complex Android customization. It first describes a novel vulnerability Hare and proves that it is security critical and extensive affecting devices from major vendors. A new tool is proposed to detect the Hare problem and to protect affected devices. This dissertation further discovers security configuration changes through a systematic differential analysis among custom devices from different vendors and demonstrates that they could lead to severe vulnerabilities if introduced unintentionally

A³: An Extensible Platform for Application-Aware Anonymity

This paper presents the design and implementation of Application-Aware Anonymity (A³), an extensible platform for deploying anonymity-based services on the Internet. A³ allows applications to tailor their anonymity properties and performance characteristics according to specific communication requirements. To support flexible path construction, A³ exposes a declarative language (A³LOG) that enables applications to compactly specify path selection and instantiation policies executed by a declarative networking engine. We demonstrate that our declarative language is sufficiently expressive to encode novel multi-metric performance constraints as well as existing relay selection algorithms employed by Tor and other anonymity systems, using only a few lines of concise code. We experimentally evaluate the A³ system using a combination of trace-driven simulations and deployment on Planet- Lab. Our experimental results demonstrate that A3 can flexibly support a wide range of path selection and instantiation strategies at low performance overhead

Private and censorship-resistant communication over public networks

Society’s increasing reliance on digital communication networks is creating unprecedented opportunities for wholesale surveillance and censorship. This thesis investigates the use of public networks such as the Internet to build robust, private communication systems that can resist monitoring and attacks by powerful adversaries such as national governments. We sketch the design of a censorship-resistant communication system based on peer-to-peer Internet overlays in which the participants only communicate directly with people they know and trust. This ‘friend-to-friend’ approach protects the participants’ privacy, but it also presents two significant challenges. The first is that, as with any peer-to-peer overlay, the users of the system must collectively provide the resources necessary for its operation; some users might prefer to use the system without contributing resources equal to those they consume, and if many users do so, the system may not be able to survive. To address this challenge we present a new game theoretic model of the problem of encouraging cooperation between selfish actors under conditions of scarcity, and develop a strategy for the game that provides rational incentives for cooperation under a wide range of conditions. The second challenge is that the structure of a friend-to-friend overlay may reveal the users’ social relationships to an adversary monitoring the underlying network. To conceal their sensitive relationships from the adversary, the users must be able to communicate indirectly across the overlay in a way that resists monitoring and attacks by other participants. We address this second challenge by developing two new routing protocols that robustly deliver messages across networks with unknown topologies, without revealing the identities of the communication endpoints to intermediate nodes or vice versa. The protocols make use of a novel unforgeable acknowledgement mechanism that proves that a message has been delivered without identifying the source or destination of the message or the path by which it was delivered. One of the routing protocols is shown to be robust to attacks by malicious participants, while the other provides rational incentives for selfish participants to cooperate in forwarding messages

Improving Security and Performance in Low Latency Anonymous Networks

Conventional wisdom dictates that the level of anonymity offered by low latency anonymity networks increases as the user base grows. However, the most significant obstacle to increased adoption of such systems is that their security and performance properties are perceived to be weak. In an effort to help foster adoption, this dissertation aims to better understand and improve security, anonymity, and performance in low latency anonymous communication systems. To better understand the security and performance properties of a popular low latency anonymity network, we characterize Tor, focusing on its application protocol distribution, geopolitical client and router distributions, and performance. For instance, we observe that peer-to-peer file sharing protocols use an unfair portion of the network’s scarce bandwidth. To reduce the congestion produced by bulk downloaders in networks such as Tor, we design, implement, and analyze an anonymizing network tailored specifically for the BitTorrent peer-to-peer file sharing protocol. We next analyze Tor’s security and anonymity properties and empirically show that Tor is vulnerable to practical end-to-end traffic correlation attacks launched by relatively weak adversaries that inflate their bandwidth claims to attract traffic and thereby compromise key positions on clients’ paths. We also explore the security and performance trade-offs that revolve around path length design decisions and we show that shorter paths offer performance benefits and provide increased resilience to certain attacks. Finally, we discover a source of performance degradation in Tor that results from poor congestion and flow control. To improve Tor’s performance and grow its user base, we offer a fresh approach to congestion and flow control inspired by techniques from IP and ATM networks

A Comprehensive Security Framework for Securing Sensors in Smart Devices and Applications

This doctoral dissertation introduces novel security frameworks to detect sensor-based threats on smart devices and applications in smart settings such as smart home, smart office, etc. First, we present a formal taxonomy and in-depth impact analysis of existing sensor-based threats to smart devices and applications based on attack characteristics, targeted components, and capabilities. Then, we design a novel context-aware intrusion detection system, 6thSense, to detect sensor-based threats in standalone smart devices (e.g., smartphone, smart watch, etc.). 6thSense considers user activity-sensor co-dependence in standalone smart devices to learn the ongoing user activity contexts and builds a context-aware model to distinguish malicious sensor activities from benign user behavior. Further, we develop a platform-independent context-aware security framework, Aegis, to detect the behavior of malicious sensors and devices in a connected smart environment (e.g., smart home, offices, etc.). Aegis observes the changing patterns of the states of smart sensors and devices for user activities in a smart environment and builds a contextual model to detect malicious activities considering sensor-device-user interactions and multi-platform correlation. Then, to limit unauthorized and malicious sensor and device access, we present, kratos, a multi-user multi-device-aware access control system for smart environment and devices. kratos introduces a formal policy language to understand diverse user demands in smart environment and implements a novel policy negotiation algorithm to automatically detect and resolve conflicting user demands and limit unauthorized access. For each contribution, this dissertation presents novel security mechanisms and techniques that can be implemented independently or collectively to secure sensors in real-life smart devices, systems, and applications. Moreover, each contribution is supported by several user and usability studies we performed to understand the needs of the users in terms of sensor security and access control in smart devices and improve the user experience in these real-time systems

An Empirical Analysis of Security and Privacy in Health and Medical Systems

Healthcare reform, regulation, and adoption of technology such as wearables are substantially changing both the quality of care and how we receive it. For example, health and fitness devices contain sensors that collect data, wireless interfaces to transmit data, and cloud infrastructures to aggregate, analyze, and share data. FDA-defined class III devices such as pacemakers will soon share these capabilities. While technological growth in health care is clearly beneficial, it also brings new security and privacy challenges for systems, users, and regulators. We group these concepts under health and medical systems to connect and emphasize their importance to healthcare. Challenges include how to keep user health data private, how to limit and protect access to data, and how to securely store and transmit data while maintaining interoperability with other systems. The most critical challenge unique to healthcare is how to balance security and privacy with safety and utility concerns. Specifically, a life-critical medical device must fail-open (i.e., work regardless) in the event of an active threat or attack. This dissertation examines some of these challenges and introduces new systems that not only improve security and privacy but also enhance workflow and usability. Usability is important in this context because a secure system that inhibits workflow is often improperly used or circumvented. We present this concern and our solution in its respective chapter. Each chapter of this dissertation presents a unique challenge, or unanswered question, and solution based on empirical analysis. We present a survey of related work in embedded health and medical systems. The academic and regulatory communities greatly scrutinize the security and privacy of these devices because of their primary function of providing critical care. What we find is that securing embedded health and medical systems is hard, done incorrectly, and is analogous to non-embedded health and medical systems such as hospital servers, terminals, and personally owned mobile devices. A policy called bring your own device (BYOD) allows the use and integration of mobile devices in the workplace. We perform an analysis of Apple iMessage which both implicates BYOD in healthcare and secure messaging protocols used by health and medical systems. We analyze direct memory access engines, a special-purpose piece of hardware to transfer data into and out of main memory, and show that we can chain together memory transfers to perform arbitrary computation. This result potentially affects all computing systems used for healthcare. We also examine HTML5 web workers as they provide stealthy computation and covert communication. This finding is relevant to web applications such as personal and electronic health record portals. We design and implement two novel and secure health and medical systems. One is a wearable device that addresses the problem of authenticating a user (e.g., physician) to a terminal in a usable way. The other is a light-weight and low-cost wireless device we call Beacon+. This device extends the design of Apple's iBeacon specification with unspoofable, temporal, and authenticated advertisements; of which, enables secure location sensing applications that could improve numerous healthcare processes

Privacy Preserving Enforcement of Sensitive Policies in Outsourced and Distributed Environments

The enforcement of sensitive policies in untrusted environments is still an open challenge for policy-based systems. On the one hand, taking any appropriate security decision requires access to these policies. On the other hand, if such access is allowed in an untrusted environment then confidential information might be leaked by the policies. The key challenge is how to enforce sensitive policies and protect content in untrusted environments. In the context of untrusted environments, we mainly distinguish between outsourced and distributed environments. The most attractive paradigms concerning outsourced and distributed environments are cloud computing and opportunistic networks, respectively. In this dissertation, we present the design, technical and implementation details of our proposed policy-based access control mechanisms for untrusted environments. First of all, we provide full confidentiality of access policies in outsourced environments, where service providers do not learn private information about policies. We support expressive policies and take into account contextual information. The system entities do not share any encryption keys. For complex user management, we offer the full-fledged Role-Based Access Control (RBAC) policies. In opportunistic networks, we protect content by specifying expressive policies. In our proposed approach, brokers match subscriptions against policies associated with content without compromising privacy of subscribers. As a result, unauthorised brokers neither gain access to content nor learn policies and authorised nodes gain access only if they satisfy policies specified by publishers. Our proposed system provides scalable key management in which loosely-coupled publishers and subscribers communicate without any prior contact. Finally, we have developed a prototype of the system that runs on real smartphones and analysed its performance.Comment: Ph.D. Dissertation. http://eprints-phd.biblio.unitn.it/1124

Impact of EU Medical Device Directive on Medical Device Software

Directive 2007/47/EC of the European Parliament amending Medical Device Directive (MDD) provides medical device manufacturers with a compliance framework. However, the effects of the amendments to the MDD on competition in the U.S. medical device software industry are unknown. This study examined the impact of this directive on the competitiveness of U.S. medical device software companies, the safety and efficacy of medical device software, employee training, and recruitment. The conceptual framework for this study included 3 dimensions of medical device regulations: safety, performance, and reliability. The overall research design was a concurrent mixed method study using both quantitative and qualitative techniques. The qualitative techniques involved case studies of 5 purposively selected companies. Data collection involved both surveys and interviews. The sample consisted of 56 employees within medical device firms with markets around the European regions. Qualitative data analysis consisted of descriptive thematic analysis along the study questions and hypotheses and summative evaluation. Quantitative data analysis included descriptive statistics and correlation to test the 4 hypotheses. The results suggested that the MDD has realigned medical device software manufacturing practices, and US medical device companies have gained global competitiveness in improving product safety and increasing sales revenue. Key recommendations to medical device manufacturers include adopting MDD 93/42/EEC, using model-based approaches, and being comprehensive in model use. Adopting the MDD will provide positive social change to patients, as human safety improves with better product quality while companies experience fewer product recalls