2,473 research outputs found

    A ROAD TRAFFIC VIOLATION DETECTION & REPORTING SYSTEM

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    This study presents a police-less multi-party traffic violation detection and reporting system, that does not rely on costly infrastructure or the presence of law enforcement. It relies solely on broadcast messages among vehicles and report delivery to the transportation authority. Firstly, a vehicle is modeled as an automaton (in computational sense) that has its own state and has a read access to the state of other automata of other vehicles in a neighborhood of fixed size. The common traffic rules and communication rules make the program of these automata that guide the transitions of the vehicles in space and time. By observing the transitions of the vehicles in their neighborhood, a vehicle can decide if these comply with the traffic rules encoded in the system. Whenever a transition is not performed according to the program, a violation occurs. These violations are reported and witnessed to the transportation authority by the vehicles in the neighborhood which act as witnesses and reporters. The system is able find the location and real identity of any vehicle whenever it commits a rule violation in traffic with a lightweight protocol. Yet, the system preserves privacy and allows no false positives

    Attack graph approach to dynamic network vulnerability analysis and countermeasures

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    A thesis submitted to the University of Bedfordshire, in partial fulfilment of the requirements for the degree of Doctor of PhilosophyIt is widely accepted that modern computer networks (often presented as a heterogeneous collection of functioning organisations, applications, software, and hardware) contain vulnerabilities. This research proposes a new methodology to compute a dynamic severity cost for each state. Here a state refers to the behaviour of a system during an attack; an example of a state is where an attacker could influence the information on an application to alter the credentials. This is performed by utilising a modified variant of the Common Vulnerability Scoring System (CVSS), referred to as a Dynamic Vulnerability Scoring System (DVSS). This calculates scores of intrinsic, time-based, and ecological metrics by combining related sub-scores and modelling the problem’s parameters into a mathematical framework to develop a unique severity cost. The individual static nature of CVSS affects the scoring value, so the author has adapted a novel model to produce a DVSS metric that is more precise and efficient. In this approach, different parameters are used to compute the final scores determined from a number of parameters including network architecture, device setting, and the impact of vulnerability interactions. An attack graph (AG) is a security model representing the chains of vulnerability exploits in a network. A number of researchers have acknowledged the attack graph visual complexity and a lack of in-depth understanding. Current attack graph tools are constrained to only limited attributes or even rely on hand-generated input. The automatic formation of vulnerability information has been troublesome and vulnerability descriptions are frequently created by hand, or based on limited data. The network architectures and configurations along with the interactions between the individual vulnerabilities are considered in the method of computing the Cost using the DVSS and a dynamic cost-centric framework. A new methodology was built up to present an attack graph with a dynamic cost metric based on DVSS and also a novel methodology to estimate and represent the cost-centric approach for each host’ states was followed out. A framework is carried out on a test network, using the Nessus scanner to detect known vulnerabilities, implement these results and to build and represent the dynamic cost centric attack graph using ranking algorithms (in a standardised fashion to Mehta et al. 2006 and Kijsanayothin, 2010). However, instead of using vulnerabilities for each host, a CostRank Markov Model has developed utilising a novel cost-centric approach, thereby reducing the complexity in the attack graph and reducing the problem of visibility. An analogous parallel algorithm is developed to implement CostRank. The reason for developing a parallel CostRank Algorithm is to expedite the states ranking calculations for the increasing number of hosts and/or vulnerabilities. In the same way, the author intends to secure large scale networks that require fast and reliable computing to calculate the ranking of enormous graphs with thousands of vertices (states) and millions of arcs (representing an action to move from one state to another). In this proposed approach, the focus on a parallel CostRank computational architecture to appraise the enhancement in CostRank calculations and scalability of of the algorithm. In particular, a partitioning of input data, graph files and ranking vectors with a load balancing technique can enhance the performance and scalability of CostRank computations in parallel. A practical model of analogous CostRank parallel calculation is undertaken, resulting in a substantial decrease in calculations communication levels and in iteration time. The results are presented in an analytical approach in terms of scalability, efficiency, memory usage, speed up and input/output rates. Finally, a countermeasures model is developed to protect against network attacks by using a Dynamic Countermeasures Attack Tree (DCAT). The following scheme is used to build DCAT tree (i) using scalable parallel CostRank Algorithm to determine the critical asset, that system administrators need to protect; (ii) Track the Nessus scanner to determine the vulnerabilities associated with the asset using the dynamic cost centric framework and DVSS; (iii) Check out all published mitigations for all vulnerabilities. (iv) Assess how well the security solution mitigates those risks; (v) Assess DCAT algorithm in terms of effective security cost, probability and cost/benefit analysis to reduce the total impact of a specific vulnerability

    Robust and private computations of mobile agent alliances

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    An Analysis of Computer Systems for the Secure Creation and Verification of User Instructions

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    The ongoing digitisation of previously analogue systems through the Fourth Industrial Revolution transforms modern societies. Almost every citizen and businesses operating in most parts of the economy are increasingly dependent on the ability of computer systems to accurately execute people's command. This requires efficient data processing capabilities and effective data input methods that can accurately capture and process instructions given by a user. This thesis is concerned with the analysis of state-of-the-art technologies for reliable data input through three case studies. In the first case study, we analyse the UI of Windows 10 and macOS 10.14 for their ability to capture accurate input from users intending to erase data. We find several shortcomings in how both OS support users in identifying and selecting operations that match their intentions and propose several improvements. The second study investigates the use of transaction authentication technology in online banking to preserve the integrity of transaction data in the presence of financial malware. We find a complex interplay of personal and sociotechnical factors that affect whether people successfully secure their transactions, derive representative personas, and propose a novel transaction authentication mechanism that ameliorates some of these factors. In the third study, we analyse the Security Code AutoFill feature in iOS and macOS and its interactions with security processes of remote servers that require users to handle security codes delivered via SMS. We find novel security risks arising from this feature's design and propose amendments, some of which were implemented by Apple. From these case studies, we derive general insights on latent failure as causes for human error that extend the Swiss Cheese model of human error to non-work environments. These findings consequently extend the Human Factors Analysis and Classification System and can be applied to human error incident investigations

    Achieving cyber resiliency against lateral movement through detection and response

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    Systems and attacks are becoming more complex, and classical cyber security methods are failing to protect and secure those systems. We believe that systems must be built to be resilient to attacks. Cyber resilience is a dynamic protection strategy that aims to stop cyber attacks while maintaining an acceptable level of service. The strategy monitors a system to detect cyber incidents, and dynamically changes the state of the system to learn about the incidents, contain an attack, and recover. Thus, instead of being perfectly protected, a cyber-resilient system survives a cyber incident by containing the attack and recovering while maintaining service. Cyber resiliency has the potential to secure the modern systems that control our critical infrastructure. However, several practical and theoretical challenges hinder the development of cyber-resilient architectures. In particular, an architecture needs to support and make use of a large amount of monitoring; the problem is especially serious for a large network in which hosts send low-level information for fusion. The problem is not only computational; the semantics of the data also creates a challenge. In combining information from multiple sources and across multiple abstractions, we need to realize that the sources are describing different events in the system which are occurring at varying time scales. Moreover, the system is dependent on the integrity of the monitoring data when estimating the state of the system. The estimated state is used to detect malicious activities and to drive responses. The integrity of the monitoring data is critical to making “correct” decisions that are not influenced by the attacker. In addition, choosing an appropriate response to specific attacks requires knowledge of the at- tackers’ behavior, i.e., an attacker model. If the attacker model is wrong, then the responses selected by the mechanism will be ineffective. Finally, the response mechanisms need to be proven effective in maintaining the resilience of the system. Proving such properties is particularly challenging when the systems are highly complex. In this dissertation, we propose a resiliency architecture that uses a model of the system to deploy monitors, estimates the state of the system using monitor data, and selects responses to contain and recover from attacks while maintaining service. Then we describe our design for the essential components of the said resiliency architecture for a multitude of systems including operating systems, hosts, and enterprise net- works, to address lateral movement attacks. Specifically, we have built components that address monitor design, fusion of monitoring data, and response. Our pieces address the challenges that face cyber-resilient architectures. We set out to provide resilience against lateral movement. Lateral movement is a step taken by an attacker to shift his or her position from an initial compromised host into a target host with high value. First, we designed a host-level monitor Kobra that generates different estimations of the state of a host. Kobra combines the various aspects of application behavior into multiple views: (1) a discrete time signal used for anomaly detection, and (2) a host-level process communication graph to correlate events that happen in a network. We use the host correlations to generate chains of network events that correspond to suspicious lateral movement behavior. We use a novel fusion framework that enables us to fuse monitoring events for different sources over a hierarchy. Finally, we respond to lateral movement by changing the topology and healing rates in the network. The changes are enacted by a feedback controller to slow down and stop the spread of the attack. Since our cyber resiliency architecture depends on the integrity of the monitoring data, we propose PowerAlert, an out-of-box integrity checker, to establish the “trustworthiness” of a machine. PowerAlert is resilient to attacker evasion and adaptation. It uses the current drawn by the CPU, measured using an external probe, to confirm that the machine executed the check as expected. To prevent an attacker from evading PowerAlert, we use an optimal initiation strategy, and to resist adaptation, we use randomly generated integrity-checking programs. We pick the optimal initiation strategy by modeling the problem of low-cost integrity checking when an attacker is attempting to evade detection as a continuous-time game called Tireless. The optimal strategy is the Nash equilibrium that optimizes the defender’s cost of checking and utility of detection against an adaptive attacker
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