Biblio

In this paper we describe and share with the research community, a significant smartphone dataset obtained from an ongoing long-term data collection experiment. The dataset currently contains 10 billion data records from 30 users collected over a period of 1.6 years and an additional 20 users for 6 months (totaling 50 active users currently participating in the experiment). The experiment involves two smartphone agents: SherLock and Moriarty. SherLock collects a wide variety of software and sensor data at a high sample rate. Moriarty perpetrates various attacks on the user and logs its activities, thus providing labels for the SherLock dataset. The primary purpose of the dataset is to help security professionals and academic researchers in developing innovative methods of implicitly detecting malicious behavior in smartphones. Specifically, from data obtainable without superuser (root) privileges. To demonstrate possible uses of the dataset, we perform a basic malware analysis and evaluate a method of continuous user authentication.

We introduce a model for differentially private analysis of weighted graphs in which the graph topology (υ,ε) is assumed to be public and the private information consists only of the edge weights ω : ε → R+. This can express hiding congestion patterns in a known system of roads. Differential privacy requires that the output of an algorithm provides little advantage, measured by privacy parameters ε and δ, for distinguishing between neighboring inputs, which are thought of as inputs that differ on the contribution of one individual. In our model, two weight functions w,w' are considered to be neighboring if they have l1 distance at most one. We study the problems of privately releasing a short path between a pair of vertices and of privately releasing approximate distances between all pairs of vertices. We are concerned with the approximation error, the difference between the length of the released path or released distance and the length of the shortest path or actual distance. For the problem of privately releasing a short path between a pair of vertices, we prove a lower bound of Ω(textbarυtextbar) on the additive approximation error for fixed privacy parameters ε,δ. We provide a differentially private algorithm that matches this error bound up to a logarithmic factor and releases paths between all pairs of vertices, not just a single pair. The approximation error achieved by our algorithm can be bounded by the number of edges on the shortest path, so we achieve better accuracy than the worst-case bound for pairs of vertices that are connected by a low-weight path consisting of o(textbarυtextbar) vertices. For the problem of privately releasing all-pairs distances, we show that for trees we can release all-pairs distances with approximation error \$O(log2.5textbarυtextbar) for fixed privacy parameters. For arbitrary bounded-weight graphs with edge weights in [0,M] we can brelease all distances with approximation error Õ(√textgreater(textbarυtextbarM).

Biometric authentication schemes are frequently used to establish the identity of a user. Often, a trusted hardware device is used to decide if a provided biometric feature is sufficiently close to the features stored by the legitimate user during enrollment. In this paper, we address the question whether the stored features can be extracted with side-channel attacks. We consider several models for types of leakage that are relevant specifically for fingerprint verification, and show results for attacks against the Bozorth3 and a custom matching algorithm. This work shows an interesting path for future research on the susceptibility of biometric algorithms towards side-channel attacks.

Video surveillance has been widely adopted to ensure home security in recent years. Most video encoding standards such as H.264 and MPEG-4 compress the temporal redundancy in a video stream using difference coding, which only encodes the residual image between a frame and its reference frame. Difference coding can efficiently compress a video stream, but it causes side-channel information leakage even though the video stream is encrypted, as reported in this paper. Particularly, we observe that the traffic patterns of an encrypted video stream are different when a user conducts different basic activities of daily living, which must be kept private from third parties as obliged by HIPAA regulations. We also observe that by exploiting this side-channel information leakage, attackers can readily infer a user's basic activities of daily living based on only the traffic size data of an encrypted video stream. We validate such an attack using two off-the-shelf cameras, and the results indicate that the user's basic activities of daily living can be recognized with a high accuracy.

This paper proposes a novel measure for edge significance considering quantity propagation in a graph. Our method utilizes a pseudo propagation process brought by solving a problem of a load balancing on nodes. Edge significance is defined as a difference of propagation in a graph with an edge to without it. The simulation compares our proposed method with the traditional betweenness centrality in order to obtain differences of our measure to a type of centrality, which considers propagation process in a graph.

Beginning the analysis of new data is often difficult as modern datasets can be overwhelmingly large. With visual analytics in particular, displays of large datasets quickly become crowded and unclear. Through observing the practices of analysts working with the event sequence visualization tool EventFlow, we identified three techniques to reduce initial visual complexity by reducing the number of event categories resulting in a simplified overview. For novice users, we suggest an initial pair of event categories to display. For advanced users, we provide six ranking metrics and display all pairs in a ranked list. Finally, we present the Event Category Matrix (ECM), which simultaneously displays overviews of every event category pair. In this work, we report on the development of these techniques through two formative usability studies and the improvements made as a result. The goal of our work is to investigate strategies that help users overcome the challenges associated with initial visual complexity and to motivate the use of simplified overviews in temporal event sequence analysis.

We introduce a system-level Simulation and Analysis Engine (SAE) framework based on dynamic binary instrumentation for fine-grained and customizable instruction-level introspection of everything that executes on the processor. SAE can instrument the BIOS, kernel, drivers, and user processes. It can also instrument multiple systems simultaneously using a single instrumentation interface, which is essential for studying scale-out applications. SAE is an x86 instruction set simulator designed specifically to enable rapid prototyping, evaluation, and validation of architectural extensions and program analysis tools using its flexible APIs. It is fast enough to execute full platform workloads–-a modern operating system can boot in a few minutes–-thus enabling research, evaluation, and validation of complex functionalities related to multicore configurations, virtualization, security, and more. To reach high speeds, SAE couples tightly with a virtual platform and employs both a just-in-time (JIT) compiler that helps simulate simple instructions efficiently and a fast interpreter for simulating new or complex instructions. We describe SAE's architecture and instrumentation engine design and show the framework's usefulness for single- and multi-system architectural and program analysis studies.

Riding on the success of SDN for enterprise and data center networks, recently researchers have shown much interest in applying SDN for critical infrastructures. A key concern, however, is the vulnerability of the SDN controller as a single point of failure. In this paper, we develop a cyber-physical simulation platform that interconnects Mininet (an SDN emulator), hardware SDN switches, and PowerWorld (a high-fidelity, industry-strength power grid simulator). We report initial experiments on how a number of representative controller faults may impact the delay of smart grid communications. We further evaluate how this delay may affect the performance of the underlying physical system, namely automatic gain control (AGC) as a fundamental closed-loop control that regulates the grid frequency to a critical nominal value. Our results show that when the fault-induced delay reaches seconds (e.g., more than four seconds in some of our experiments), degradation of the AGC becomes evident. Particularly, the AGC is most vulnerable when it is in a transient following say step changes in loading, because the significant state fluctuations will exacerbate the effects of using a stale system state in the control.

Internet censorship is used in many parts of the world to prohibit free access to online information. Different techniques such as IP address or URL blocking, DNS hijacking, or deep packet inspection are used to block access to specific content on the Internet. In response, several censorship circumvention systems were proposed that attempt to bypass existing filters. Especially systems that hide the communication in different types of cover protocols attracted a lot of attention. However, recent research results suggest that this kind of covert traffic can be easily detected by censors. In this paper, we present SkypeLine, a censorship circumvention system that leverages Direct-Sequence Spread Spectrum (DSSS) based steganography to hide information in Voice-over-IP (VoIP) communication. SkypeLine introduces two novel modulation techniques that hide data by modulating information bits on the voice carrier signal using pseudo-random, orthogonal noise sequences and repeating the spreading operation several times. Our design goals focus on undetectability in presence of a strong adversary and improved data rates. As a result, the hiding is inconspicuous, does not alter the statistical characteristics of the carrier signal, and is robust against alterations of the transmitted packets. We demonstrate the performance of SkypeLine based on two simulation studies that cover the theoretical performance and robustness. Our measurements demonstrate that the data rates achieved with our techniques substantially exceed existing DSSS approaches. Furthermore, we prove the real-world applicability of the presented system with an exemplary prototype for Skype.

Cloud computing is rapidly reshaping the server administration landscape. The widespread use of virtualization and the increasingly high server consolidation ratios, in particular, have introduced unprecedented security challenges for users, increasing the exposure to intrusions and opening up new opportunities for attacks. Deploying security mechanisms in the hypervisor to detect and stop intrusion attempts is a promising strategy to address this problem. Existing hypervisor-based solutions, however, are typically limited to very specific classes of attacks and introduce exceedingly high performance overhead for production use. In this paper, we present Slick (Storage-Level Intrusion ChecKer), an intrusion detection system (IDS) for virtualized storage devices. Slick detects intrusion attempts by efficiently and transparently monitoring write accesses to critical regions on storage devices. The low-overhead monitoring component operates entirely inside the hypervisor, with no introspection or modifications required in the guest VMs. Using Slick, users can deploy generic IDS rules to detect a broad range of real-world intrusions in a flexible and practical way. Experimental results confirm that Slick is effective at enhancing the security of virtualized servers, while imposing less than 5% overhead in production.

Security vulnerability assessment is an important process that must be conducted against any system before the deployment, and emerging technologies are no exceptions. Software-Defined Networking (SDN) has aggressively evolved in the past few years and is now almost at the early adoption stage. At this stage, the attack surface of SDN should be thoroughly investigated and assessed in order to mitigate possible security breaches against SDN. Inspired by the necessity, we reveal three attack scenarios that leverage SDN application to attack SDNs, and test the attack scenarios against three of the most popular SDN controllers available today. In addition, we discuss the possible defense mechanisms against such application-originated attacks.

Recently, wireless home routers increasingly become smart. While these smart routers provide rich functionalities to users, they also raise security concerns. Since a smart home router may process and store personal data for users, once compromised, these sensitive information will be exposed. Unfortunately, current operating systems on home routers are far from secure. As a consequence, users are facing a difficult tradeoff between functionality and privacy risks. This paper attacks this dilemma with a novel SEAL architecture for home routers. SEAL leverages the ARM TrustZone technology to divide a conventional router OS (i.e., Linux) in a non-secure/normal world. All sensitive user data are shielded from the normal world using encryption. Modules (called applets) that process the sensitive data are located in a secure world and confined in secure sandboxes provided by a tiny secure OS. We report the system design of SEAL and our preliminary implementation and evaluation results.

Over the last few decades, accessibility scenarios have undergone a drastic change. Today the way people access information and resources is quite different from the age when internet was not evolved. The evolution of the Internet has made remarkable, epoch-making changes and has become the backbone of smart city. The vision of smart city revolves around seamless connectivity. Constant connectivity can provide uninterrupted services to users such as e-governance, e-banking, e-marketing, e-shopping, e-payment and communication through social media. And to provide uninterrupted services to such applications to citizens is our prime concern. So this paper focuses on smart handoff framework for next generation heterogeneous networks in smart cities to provide all time connectivity to anyone, anyhow and anywhere. To achieve this, three strategies have been proposed for handoff initialization phase-Mobile controlled, user controlled and network controlled handoff initialization. Each strategy considers a different set of parameters. Results show that additional parameters with RSSI and adaptive threshold and hysteresis solve ping-pong and corner effect problems in smart city.

We examine the security of home smart locks: cyber-physical devices that replace traditional door locks with deadbolts that can be electronically controlled by mobile devices or the lock manufacturer's remote servers. We present two categories of attacks against smart locks and analyze the security of five commercially-available locks with respect to these attacks. Our security analysis reveals that flaws in the design, implementation, and interaction models of existing locks can be exploited by several classes of adversaries, allowing them to learn private information about users and gain unauthorized home access. To guide future development of smart locks and similar Internet of Things devices, we propose several defenses that mitigate the attacks we present. One of these defenses is a novel approach to securely and usably communicate a user's intended actions to smart locks, which we prototype and evaluate. Ultimately, our work takes a first step towards illuminating security challenges in the system design and novel functionality introduced by emerging IoT systems.

The explosion in Internet-connected household devices, such as light-bulbs, smoke-alarms, power-switches, and webcams, is creating new vectors for attacking "smart-homes" at an unprecedented scale. Common perception is that smart-home IoT devices are protected from Internet attacks by the perimeter security offered by home routers. In this paper we demonstrate how an attacker can infiltrate the home network via a doctored smart-phone app. Unbeknownst to the user, this app scouts for vulnerable IoT devices within the home, reports them to an external entity, and modifies the firewall to allow the external entity to directly attack the IoT device. The ability to infiltrate smart-homes via doctored smart-phone apps demonstrates that home routers are poor protection against Internet attacks and highlights the need for increased security for IoT devices.

This paper presents general techniques for verifying virtually synchronous distributed control systems with interconnected physical environments. Such cyber-physical systems (CPSs) are notoriously hard to verify, due to their combination of nontrivial continuous dynamics, network delays, imprecise local clocks, asynchronous communication, etc. To simplify their analysis, we first extend the PALS methodology–-that allows to abstract from the timing of events, asynchronous communication, network delays, and imprecise clocks, as long as the infrastructure guarantees bounds on the network delays and clock skews–-from real-time to hybrid systems. We prove a bisimulation equivalence between Hybrid PALS synchronous and asynchronous models. We then show how various verification problems for synchronous Hybrid PALS models can be reduced to SMT solving over nonlinear theories of the real numbers. We illustrate the Hybrid PALS modeling and verification methodology on a number of CPSs, including a control system for turning an airplane.

This study aims to identify and quantify applications that are making use of port numbers that are typically associated with other major Internet applications (i.e. port 53, 80, 123, 443, 8000 and 8080) to bypass port-based traffic controls such as firewalls. We use lightweight packet inspection to examine each flow observed using these ports on our campus network over the course of a week in September 2015 and identify applications that are producing network traffic that does not match the expected application for each port. We find that there are numerous programs that co-opt the port numbers of major Internet applications on our campus, many of which are Chinese in origin and are not recognized by existing traffic classification tools. As a result of our investigation, new rules for identifying over 20 new applications have been made available to the research community.

Social Engineering is a kind of advance persistent threat (APT) that gains private and sensitive information through social networks or other types of communication. The attackers can use social engineering to obtain access into social network accounts and stays there undetected for a long period of time. The purpose of the attack is to steal sensitive data and spread false information rather than to cause direct damage. Such targets can include Facebook accounts of government agencies, corporations, schools or high-profile users. We propose to use IDS, Intrusion Detection System, to battle such attacks. What the social engineering does is try to gain easy access, so that the attacks can be repeated and ongoing. The focus of this study is to find out how this type of attacks are carried out so that they can properly detected by IDS in future research.

The exploitation of the opportunistic infrastructure via Device-to-Device (D2D) communication is a critical component towards the adoption of new paradigms such as edge and fog computing. While a lot of work has demonstrated the great potential of D2D communication, it is still unclear whether the benefits of the D2D approach can really be leveraged in practice. In this paper, we develop a software sensor, namely Detector, which senses the infrastructure in proximity of a mobile user. We analyze and evaluate D2D on the wild, i.e., not in simulations. We found that in a realistic environment, a mobile is always co-located in proximity to at least one other mobile device throughout the day. This suggests that a device can schedule tasks processing in coordination with other devices, potentially more powerful, instead of handling the processing of the tasks by itself.

Security testing is a pivotal activity in engineering secure software. It consists of two phases: generating attack inputs to test the system, and assessing whether test executions expose any vulnerabilities. The latter phase is known as the security oracle problem. In this work, we present SOFIA, a Security Oracle for SQL-Injection Vulnerabilities. SOFIA is programming-language and source-code independent, and can be used with various attack generation tools. Moreover, because it does not rely on known attacks for learning, SOFIA is meant to also detect types of SQLi attacks that might be unknown at learning time. The oracle challenge is recast as a one-class classification problem where we learn to characterise legitimate SQL statements to accurately distinguish them from SQLi attack statements. We have carried out an experimental validation on six applications, among which two are large and widely-used. SOFIA was used to detect real SQLi vulnerabilities with inputs generated by three attack generation tools. The obtained results show that SOFIA is computationally fast and achieves a recall rate of 100% (i.e., missing no attacks) with a low false positive rate (0.6%).

Electrical substations are crucial for power grids. A number of international standards, such as IEC 60870 and 61850, have emerged to enable remote and automated control over substations. However, owing to insufficient security consideration in their design and implementation, the resulting systems could be vulnerable to cyber attacks. As a result, the modernization of a large number of substations dramatically increases the scale of potential damage successful attacks can cause on power grids. To counter such a risk, one promising direction is to design and deploy an additional layer of defense at the substations. However, it remains a challenge to evaluate various substation cybersecurity solutions in a realistic environment. In this paper, we present the design and implementation of SoftGrid, a software-based smart grid testbed for evaluating the effectiveness, performance, and interoperability of various security solutions implemented to protect the remote control interface of substations. We demonstrate the capability and usefulness of SoftGrid through a concrete case study. We plan to open-source SoftGrid to facilitate security research in related areas.

One step involved in the security engineering process is threat modeling. Threat modeling involves understanding the complexity of the system and identifying all of the possible threats, regardless of whether or not they can be exploited. Proper identification of threats and appropriate selection of countermeasures reduces the ability of attackers to misuse the system. This paper presents a quantitative, integrated threat modeling approach that merges software and attack centric threat modeling techniques. The threat model is composed of a system model representing the physical and network infrastructure layout, as well as a component model illustrating component specific threats. Component attack trees allow for modeling specific component contained attack vectors, while system attack graphs illustrate multi-component, multi-step attack vectors across the system. The Common Vulnerability Scoring System (CVSS) is leveraged to provide a standardized method of quantifying the low level vulnerabilities in the attack trees. As a case study, a railway communication network is used, and the respective results using a threat modeling software tool are presented.

Software defects will lead to software running error and system crashes. In order to detect software defect as early as possible at early stage of software development, a series of machine learning approaches have been studied and applied to predict defects in software modules. Unfortunately, the imbalanceof software defect datasets brings great challenge to software defect prediction model training. In this paper, a new manifold learning based subspace learning algorithm, Discriminative Locality Alignment(DLA), is introduced into software defects prediction. Experimental results demonstrate that DLA is consistently superior to LDA (Linear Discriminant Analysis) and PCA (Principal Component Analysis) in terms of discriminate information extraction and prediction performance. In addition, DLA reveals some attractive intrinsic properties for numeric calculation, e.g. it can overcome the matrix singular problem and small sample size problem in software defect prediction.

In software quality estimation research, software defect prediction is a key topic. A defect prediction model is generally constructed using a variety of software attributes and each attribute may have positive, negative or neutral effect on a specific model. Selection of an optimal set of attributes for model development remains a vital yet unexplored issue. In this paper, we have introduced a new feature space transformation process with a normalization technique to improve the defect prediction accuracy. We proposed a feature space transformation technique and classify the instances using Support Vector Machine (SVM) with its histogram intersection kernel. The proposed method is evaluated using the data sets from NASA metric data repository and its application demonstrates acceptable accuracy.

With the rising interest of expedient, safe, and high-efficient transportation, vehicular ad hoc networks (VANETs) have turned into a critical technology in smart transportation systems. Because of the high mobility of nodes, VANETs are vulnerable to security attacks. In this paper, we propose a novel framework of software-defined VANETs with trust management. Specifically, we separate the forwarding plane in VANETs from the control plane, which is responsible for the control functionality, such as routing protocols and trust management in VANETs. Using the on-demand distance vector routing (TAODV) protocol as an example, we present a routing protocol named software-defined trust based ad hoc on-demand distance vector routing (SD-TAODV). Simulation results are presented to show the effectiveness of the proposed software-defined VANETs with trust management.