Biblio

Cover time measures the time (or number of steps) required for a mobile agent to visit each node in a network (graph) at least once. A short cover time is important for search or foraging applications that require mobile agents to quickly inspect or monitor nodes in a network, such as providing situational awareness or security. Speed can be achieved if details about the graph are known or if the agent maintains a history of visited nodes, however, these requirements may not be feasible for agents with limited resources, they are difficult in dynamic graph topologies, and they do not easily scale to large networks. This paper introduces a set-based form of heading (directional bias) that allows an agent to more efficiently explore any connected graph, static or dynamic. When deciding the next node to visit, agents are discouraged from visiting nodes that neighbor both their previous and current locations. Modifying a traditional movement method, e.g., random walk, with this concept encourages an agent to move toward nodes that are less likely to have been previously visited, reducing cover time. Simulation results with grid, scale-free, and minimum distance graphs demonstrate heading can consistently reduce cover time as compared to non-heading movement techniques.
 

One of the important direction of research in situational awareness is implementation of visual analytics techniques which can be efficiently applied when working with big security data in critical operational domains. The paper considers a visual analytics technique for displaying a set of security metrics used to assess overall network security status and evaluate the efficiency of protection mechanisms. The technique can assist in solving such security tasks which are important for security information and event management (SIEM) systems. The approach suggested is suitable for displaying security metrics of large networks and support historical analysis of the data. To demonstrate and evaluate the usefulness of the proposed technique we implemented a use case corresponding to the Olympic Games scenario.
 

This article talks about online deception, deception to them is considered as a deliberate act with the intent to mislead others while the recipients are not made aware or expect that such an act is taking place and that the goal of the deceiver is to transfer that false belief to the deceived ones. Understanding how online deception works through social media and future technologies remains a significant challenge. To address this challenge one needs to design social media applications with various rules and norms that our traditional physical space does not have.

Cyber scanning refers to the task of probing enterprise networks or Internet wide services, searching for vulnerabilities or ways to infiltrate IT assets. This misdemeanor is often the primarily methodology that is adopted by attackers prior to launching a targeted cyber attack. Hence, it is of paramount importance to research and adopt methods for the detection and attribution of cyber scanning. Nevertheless, with the surge of complex offered services from one side and the proliferation of hackers' refined, advanced, and sophisticated techniques from the other side, the task of containing cyber scanning poses serious issues and challenges. Furthermore recently, there has been a flourishing of a cyber phenomenon dubbed as cyber scanning campaigns - scanning techniques that are highly distributed, possess composite stealth capabilities and high coordination - rendering almost all current detection techniques unfeasible. This paper presents a comprehensive survey of the entire cyber scanning topic. It categorizes cyber scanning by elaborating on its nature, strategies and approaches. It also provides the reader with a classification and an exhaustive review of its techniques. Moreover, it offers a taxonomy of the current literature by focusing on distributed cyber scanning detection methods. To tackle cyber scanning campaigns, this paper uniquely reports on the analysis of two recent cyber scanning incidents. Finally, several concluding remarks are discussed.
 

Zero-day polymorphic worms pose a serious threat to the Internet security. With their ability to rapidly propagate, these worms increasingly threaten the Internet hosts and services. Not only can they exploit unknown vulnerabilities but can also change their own representations on each new infection or can encrypt their payloads using a different key per infection. They have many variations in the signatures of the same worm thus, making their fingerprinting very difficult. Therefore, signature-based defenses and traditional security layers miss these stealthy and persistent threats. This paper provides a detailed survey to outline the research efforts in relation to detection of modern zero-day malware in form of zero-day polymorphic worms.

Our vision in this paper is that agency, as the individual ability to intervene and tailor the system, is a crucial element in building trust in IoT technologies. Following up on this vision, we will first address the issue of agency, namely the individual capability to adopt free decisions, as a relevant driver in building trusted human-IoT relations, and how agency should be embedded in digital systems. Then we present the main challenges posed by existing approaches to implement this vision. We show then our proposal for a model-based approach that realizes the agency concept, including a prototype implementation.

This paper describes results of a study seeking to identify observable events related to insider sabotage. We collected information from actual insider threat cases, created chronological timelines of the incidents, identified key points in each timeline such as when attack planning began, measured the time between key events, and looked for specific observable events or patterns that insiders held in common that may indicate insider sabotage is imminent or likely. Such indicators could be used by security experts to potentially identify malicious activity at or before the time of attack. Our process included critical steps such as identifying the point of damage to the organization as well as any malicious events prior to zero hour that enabled the attack but did not immediately cause harm. We found that nearly 71% of the cases we studied had either no observable malicious action prior to attack, or had one that occurred less than one day prior to attack. Most of the events observed prior to attack were behavioral, not technical, especially those occurring earlier in the case timelines. Of the observed technical events prior to attack, nearly one third involved installation of software onto the victim organizations IT systems.

Despite considerable research on passwords, empirical studies of password strength have been limited by lack of access to plaintext passwords, small data sets, and password sets specifically collected for a research study or from low-value accounts. Properties of passwords used for high-value accounts thus remain poorly understood. We fill this gap by studying the single-sign-on passwords used by over 25,000 faculty, staff, and students at a research university with a complex password policy. Key aspects of our contributions rest on our (indirect) access to plaintext passwords. We describe our data collection methodology, particularly the many precautions we took to minimize risks to users. We then analyze how guessable the collected passwords would be during an offline attack by subjecting them to a state-of-the-art password cracking algorithm. We discover significant correlations between a number of demographic and behavioral factors and password strength. For example, we find that users associated with the computer science school make passwords more than 1.5 times as strong as those of users associated with the business school. while users associated with computer science make strong ones. In addition, we find that stronger passwords are correlated with a higher rate of errors entering them. We also compare the guessability and other characteristics of the passwords we analyzed to sets previously collected in controlled experiments or leaked from low-value accounts. We find more consistent similarities between the university passwords and passwords collected for research studies under similar composition policies than we do between the university passwords and subsets of passwords leaked from low-value accounts that happen to comply with the same policies.

Three years ago in this venue, Cook argued that in their essence, objects are what Reynolds called procedural data structures. His observation raises a natural question: if procedural data structures are the essence of objects, has this contributed to the empirical success of objects, and if so, how? This essay attempts to answer that question. After reviewing Cook's definition, I propose the term service abstractions to capture the essential nature of objects. This terminology emphasizes, following Kay, that objects are not primarily about representing and manipulating data, but are more about providing services in support of higher-level goals. Using examples taken from object-oriented frameworks, I illustrate the unique design leverage that service abstractions provide: the ability to define abstractions that can be extended, and whose extensions are interoperable in a first-class way. The essay argues that the form of interoperable extension supported by service abstractions is essential to modern software: many modern frameworks and ecosystems could not have been built without service abstractions. In this sense, the success of objects was not a coincidence: it was an inevitable consequence of their service abstraction nature.

Proofs of Retrievability (PoR), proposed by Juels and Kaliski in 2007, enable a client to store n file blocks with a cloud server so that later the server can prove possession of all the data in a very efficient manner (i.e., with constant computation and bandwidth). Although many efficient PoR schemes for static data have been constructed, only two dynamic PoR schemes exist. The scheme by Stefanov et. al. (ACSAC 2012) uses a large of amount of client storage and has a large audit cost. The scheme by Cash (EUROCRYPT 2013) is mostly of theoretical interest, as it employs Oblivious RAM (ORAM) as a black box, leading to increased practical overhead (e.g., it requires about 300 times more bandwidth than our construction). We propose a dynamic PoR scheme with constant client storage whose bandwidth cost is comparable to a Merkle hash tree, thus being very practical. Our construction outperforms the constructions of Stefanov et. al. and Cash et. al., both in theory and in practice. Specifically, for n outsourced blocks of beta bits each, writing a block requires beta+O(lambdalog n) bandwidth and O(betalog n) server computation (lambda is the security parameter). Audits are also very efficient, requiring beta+O(lambda^2log n) bandwidth. We also show how to make our scheme publicly verifiable, providing the first dynamic PoR scheme with such a property. We finally provide a very efficient implementation of our scheme.

This paper describes the research, development, and analysis performed during the Remote Suspect Identification (RSID) effort. The effort produced a keystroke dynamics sensor capable of authenticating, continuously verifying, and identifying masquerading users with equal error rates (EER) of approximately 0.054, 0.050, and 0.069, respectively. This sensor employs 11 distinct algorithms, each using between one and five keystroke features, that are fused (across features and algorithms) using a weighted majority ballot algorithm to produce rapid and accurate measurements. The RSID sensor operates discretely, quickly (using few keystrokes), and requires no additional hardware. The researchers also analyzed the difference in sensor performance across 10 demographic features using a keystroke dynamics dataset consisting of data from over 2,200 subjects. This analysis indicated that there are significant and discernible differences across age groups, ethnicities, language, handedness, height, occupation, sex, typing frequency, and typing style.

The Secure Sockets Layer (SSL) is widely used to secure data transfers on the Internet. Previous studies have shown that the state of non-browser SSL code is catastrophic across a large variety of desktop applications and libraries as well as a large selection of Android apps, leaving users vulnerable to Man-in-the-Middle attacks (MITMAs). To determine possible causes of SSL problems on all major appified platforms, we extended the analysis to the walled-garden ecosystem of iOS, analyzed software developer forums and conducted interviews with developers of vulnerable apps. Our results show that the root causes are not simply careless developers, but also limitations and issues of the current SSL development paradigm. Based on our findings, we derive a proposal to rethink the handling of SSL in the appified world and present a set of countermeasures to improve the handling of SSL using Android as a blueprint for other platforms. Our countermeasures prevent developers from willfully or accidentally breaking SSL certificate validation, offer support for extended features such as SSL Pinning and different SSL validation infrastructures, and protect users. We evaluated our solution against 13,500 popular Android apps and conducted developer interviews to judge the acceptance of our approach and found that our solution works well for all investigated apps and developers.

Cyber-Physical System(CPS) is now a new evolutional morphology of embedded systems. With features of merging computation and physical processes together, the traditional verification and simulation methods have being challenged recently. After analyzed the state-of-art of related research, a new simulation environment is studied according to the characters of a special autonomous cyber-physical system-Unmanned Aerial Vehicle, and designed to be scene-driven, modeling and reconfigurable. In this environment, a novel CPS-in-loop architecture, which can support simulations under different customized scenes, is studied firstly to ensure its opening and flexibility. And as another foundation, some dynamics models of CPS and atmospheric ones of relative sensors are introduced to simulate the motion of CPS and the change of its posture. On the basis above, the reconfigurable scene-driven mechanisms that are Based on hybrid events are mainly excogitated. Then, different scenes can be configured in terms of special verification requirements, and then each scene will be decomposed into a spatio-temporal event sequence and scheduled by a scene executor. With this environment, not only the posture of CPS, but also the autonomy of its behavior can be verified and observed. It will be meaningful for the design of such autonomous CPS.

CPS traffic characteristics is one of key techniques of Cyber-Physical Systems (CPS). A deep research of CPS network traffic characteristics can help to better plan and design CPS networks. A brief overview of the key concepts of CPS is firstly presented. Then CPS application scenarios are analyzed in details and classified. The characteristics of CPS traffic is analyzed theoretically for different CPS application scenarios. At last, the characteristics of CPS traffic is verified using NS-2 simulation.

The lack of standardization of the terms insider and insider threat has been a noted problem for researchers in the insider threat field. This paper describes the investigation of 42 different definitions of the terms insider and insider threat, with the goal of better understanding the current conceptual model of insider threat and facilitating communication in the research community.

Domain-specific languages improve ease-of-use, expressiveness and verifiability, but defining and using different DSLs within a single application remains difficult. We introduce an approach for embedded DSLs where 1) whitespace delimits DSL-governed blocks, and 2) the parsing and type checking phases occur in tandem so that the expected type of the block determines which domain-specific parser governs that block. We argue that this approach occupies a sweet spot, providing high expressiveness and ease-of-use while maintaining safe composability. We introduce the design, provide examples and describe an ongoing implementation of this strategy in the Wyvern programming language. We also discuss how a more conventional keyword-directed strategy for parsing of DSLs can arise as a special case of this type-directed strategy.

The simplest and purest practical object-oriented language designs today are seen in dynamically-typed languages, such as Smalltalk and Self. Static types, however, have potential benefits for productivity, security, and reasoning about programs. In this paper, we describe the design of Wyvern, a statically typed, pure object-oriented language that attempts to retain much of the simplicity and expressiveness of these iconic designs. Our goals lead us to combine pure object-oriented and functional abstractions in a simple, typed setting. We present a foundational object-based language that we believe to be as close as one can get to simple typed lambda calculus while keeping object-orientation. We show how this foundational language can be translated to the typed lambda calculus via standard encodings. We then define a simple extension to this language that introduces classes and show that classes are no more than sugar for the foundational object-based language. Our future intention is to demonstrate that modules and other object-oriented features can be added to our language as not more than such syntactical extensions while keeping the object-oriented core as pure as possible. The design of Wyvern closely follows both historical and modern ideas about the essence of object-orientation, suggesting a new way to think about a minimal, practical, typed core language for objects.

Specifics of an alias-free digitizer application for compressed digitizing and recording of wideband signals are considered. Signal sampling in this case is performed on the basis of picosecond resolution event timing, the digitizer actually is a subsystem of Event Timer A033-ET and specific events that are detected and then timed are the signal and reference sine-wave crossings. The used approach to development of this subsystem is described and some results of experimental studies are given.

We present a new paradigm for unification arising out of a technique commonly used in cryptographic protocol analysis tools that employ unification modulo equational theories. This paradigm relies on: (i) a decomposition of an equational theory into (R, E) where R is confluent, terminating, and coherent modulo E, and (ii) on reducing unifi- cation problems to a set of problems s =^? t under the constraint that t remains R/E-irreducible. We call this method asymmetric unification . We first present a general-purpose generic asymmetric unification algorithm.and then outline an approach for converting special-purpose conventional unification algorithms to asymmetric ones, demonstrating it for exclusive-or with uninterpreted function symbols. We demonstrate how asymmetric unification can improve performanceby running the algorithm on a set of benchmark problems. We also give results on the complexity and decidability of asymmetric unification.

 

 

Atomic sets are a synchronization mechanism in which the programmer specifies the groups of data that must be ac- cessed as a unit. The compiler can check this specifica- tion for consistency, detect deadlocks, and automatically add the primitives to prevent interleaved access. Atomic sets relieve the programmer from the burden of recognizing and pruning execution paths which lead to interleaved ac- cess, thereby reducing the potential for data races. However, manually converting programs from lock-based synchroniza- tion to atomic sets requires reasoning about the program’s concurrency structure, which can be a challenge even for small programs. Our analysis eliminates the challenge by automating the reasoning. Our implementation of the anal- ysis allowed us to derive the atomic sets for large code bases such as the Java collections framework in a matter of min- utes. The analysis is based on execution traces; assuming all traces reflect intended behavior, our analysis enables safe concurrency by preventing unobserved interleavings which may harbor latent Heisenbugs.