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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Electromagnetic Interference Attacks on Cyber-Physical Systems: Theory, Demonstration, and Defense

Dayanikli, Gokcen Yilmaz 27 August 2021 (has links)
A cyber-physical system (CPS) is a complex integration of hardware and software components to perform well-defined tasks. Up to this point, many software-based attacks targeting the network and computation layers have been reported by the researchers. However, the physical layer attacks that utilize natural phenomena (e.g., electromagnetic waves) to manipulate safety-critic signals such as analog sensor outputs, digital data, and actuation signals have recently taken the attention. The purpose of this dissertation is to detect the weaknesses of cyber-physical systems against low-power Intentional Electromagnetic Interference (IEMI) attacks and provide hardware-level countermeasures. Actuators are irreplaceable components of electronic systems that control the physically moving sections, e.g., servo motors that control robot arms. In Chapter 2, the potential effects of IEMI attacks on actuation control are presented. Pulse Width Modulation (PWM) signal, which is the industry–standard for actuation control, is observed to be vulnerable to IEMI with specific frequency and modulated–waveforms. Additionally, an advanced attacker with limited information about the victim can prevent the actuation, e.g., stop the rotation of a DC or servo motor. For some specific actuator models, the attacker can even take the control of the actuators and consequently the motion of the CPS, e.g., the flight trajectory of a UAV. The attacks are demonstrated on a fixed-wing unmanned aerial vehicle (UAV) during varying flight scenarios, and it is observed that the attacker can block or take control of the flight surfaces (e.g., aileron) which results in a crash of the UAV or a controllable change in its trajectory, respectively. Serial communication protocols such as UART or SPI are widely employed in electronic systems to establish communication between peripherals (e.g., sensors) and controllers. It is observed that an adversary with the reported three-phase attack mechanism can replace the original victim data with the 'desired' false data. In the detection phase, the attacker listens to the EM leakage of the victim system. In the signal processing phase, the exact timing of the victim data is determined from the victim EM leakage, and in the transmission phase, the radiated attack waveform replaces the original data with the 'desired' false data. The attack waveform is a narrowband signal at the victim baud rate, and in a proof–of–concept demonstration, the attacks are observed to be over 98% effective at inducing a desired bit sequence into pseudorandom UART frames. Countermeasures such as twisted cables are discussed and experimentally validated in high-IEMI scenarios. In Chapter 4, a state-of-art electrical vehicle (EV) charger is assessed in IEMI attack scenarios, and it is observed that an attacker can use low–cost RF components to inject false current or voltage sensor readings into the system. The manipulated sensor data results in a drastic increase in the current supplied to the EV which can easily result in physical damage due to thermal runaway of the batteries. The current switches, which control the output current of the EV charger, can be controlled (i.e., turned on) by relatively high–power IEMI, which gives the attacker direct control of the current supplied to the EV. The attacks on UAVs, communication systems, and EV chargers show that additional hardware countermeasures should be added to the state-of-art system design to alleviate the effect of IEMI attacks. The fiber-optic transmission and low-frequency magnetic field shielding can be used to transmit 'significant signals' or PCB-level countermeasures can be utilized which are reported in Chapter 5. / Doctor of Philosophy / The secure operation of an electronic system depends on the integrity of the signals transmitted from/to components like sensors, actuators, and controllers. Adversaries frequently aim to block or manipulate the information carried in sensor and actuation signals to disrupt the operation of the victim system with physical phenomena, e.g., infrared light or acoustic waves. In this dissertation, it is shown that low-power electromagnetic (EM) waves, with specific frequency and form devised for the victim system, can be utilized as an attack tool to disrupt, and, in some scenarios, control the operation of the system; moreover, it is shown that these attacks can be mitigated with hardware-level countermeasures. In Chapter 2, the attacks are applied to electric motors on an unmanned aerial vehicle (UAV), and it is observed that an attacker can block (i.e., crash of the UAV) or control the UAV motion with EM waves. In Chapter 3, it is shown that digital communication systems are not resilient against intentional electromagnetic interference (IEMI), either. Low–power EM waves can be utilized by attackers to replace the data in serial communication systems with a success rate %98 or more. In Chapter 4, the attacks are applied to the sensors and actuators of electric vehicle chargers with low–cost over–the–shelf amplifiers and antennas, and it is shown that EM interference attacks can manipulate the sensor data and boosts the current supplied to the EV, which can result in overheating and fire. To ensure secure electronic system operation, hardware–level defense mechanisms are discussed and validated with analytical solutions, simulations, and experiments.
62

Antifragile Communications

Lichtman, Marc Louis 16 August 2016 (has links)
Jamming is an ongoing threat that plagues wireless communications in contested areas. Unfortunately, jamming complexity and sophistication will continue to increase over time. The traditional approach to addressing the jamming threat is to harden radios, such that they sacrifice communications performance for more advanced jamming protection. To provide an escape from this trend, we investigate the previously unexplored area of jammer exploitation. This dissertation develops the concept of antifragile communications, defined as the capability for a communications system to improve in performance due to a system stressor or harsh condition. Antifragility refers to systems that increase in capability, resilience, or robustness as a result of disorder (e.g., chaos, uncertainty, stress). An antifragile system is fundamentally different from one that is resilient (i.e., able to recover from failure) and robust (i.e., able to resist failure). We apply the concept of antifragility to wireless communications through several novel strategies that all involve exploiting a communications jammer. These strategies can provide an increase in throughput, efficiency, connectivity, or covertness, as a result of the jamming attack itself. Through analysis and simulation, we show that an antifragile gain is possible under a wide array of electronic warfare scenarios. Throughout this dissertation we provide guidelines for realizing these antifragile waveforms. Other major contributions of this dissertation include the development of a communications jamming taxonomy, feasibility study of reactive jamming in a SATCOM-type scenario, and a reinforcement learning-based reactive jamming mitigation strategy, for times when an antifragile approach is not practical. Most of the jammer exploitation strategies described in this dissertation fall under the category of jammer piggybacking, meaning the communications system turns the jammer into an unwitting relay. We study this jammer piggybacking approach under a variety of reactive jamming behaviors, with emphasis on the sense-and-transmit type. One piggybacking approach involves transmitting using a specialized FSK waveform, tailored to exploit a jammer that channelizes a block of spectrum and selectively jams active subchannels. To aid in analysis, we introduce a generalized model for reactive jamming, applicable to both repeater-based and sensing-based jamming behaviors. Despite being limited to electronic warfare scenarios, we hope that this work can pave the way for further research into antifragile communications. / Ph. D.
63

Response-Based Synchrophasor Controls for Power Systems

Quint, Ryan David 25 April 2013 (has links)
The electric power grid is operated with exceptionally high levels of reliability, yet recent large-scale outages have highlighted areas for improvement in operation, control, and planning of power systems.  Synchrophasor technology may be able to address these concerns, and Phasor Measurement Units (PMUs) are actively being deployed across the Western Interconnection and North America.  Initiatives such as the Western Interconnection Synchrophasor Program (WISP) are making significant investments PMUs with the expectation that wide-area, synchronized, high-resolution measurements will improve operator situational awareness, enable advanced control strategies, and aid in planning the grid. This research is multifaceted in that it focuses on improved operator awareness and alarming as well as innovative remedial controls utilizing synchrophasors.  It integrates existing tools, controls, and infrastructure with new technology to propose applications and schemes that can be implemented for any utility.  This work presents solutions to problems relevant to the industry today, emphasizing utility design and implementation.  The Bonneville Power Administration (BPA) and Western Electricity Coordinating Council (WECC) transmission systems are used as the testing environment, and the work performed here is being explored for implementation at BPA.  However, this work is general in nature such that it can be implemented in myriad networks and control centers. A Phase Angle Alarming methodology is proposed for improving operator situational awareness.  The methodology is used for setting phase angle limits for a two-tiered angle alarming application.  PMUs are clustered using an adapted disturbance-based probabilistic rms-coherency analysis.  While the lower tier angle limits are determined using static security assessment between the PMU clusters, the higher tier limits are based on pre-contingency operating conditions that signify poorly damped post-contingency oscillation ringdown.  Data mining tools, specifically decision trees, are employed to determine critical indicators and their respective thresholds.  An application is presented as a prototype; however, the methodology may be implemented in online tools as well as offline studies. System response to disturbances is not only dependent on pre-contingency conditions but also highly dependent on post-contingency controls.  Pre-defined controls such as Special Protection Schemes (SPSs) or Remedial Action Schemes (RAS) have a substantial impact on the stability of the system.  However, existing RAS controls are generally event-driven, meaning they respond to predetermined events on the system.  This research expands an existing event-driven voltage stability RAS to a response-based scheme using synchrophasor measurements.  A rate-of-change algorithm is used to detect substantial events that may put the WECC system at risk of instability.  Pickup of this algorithm triggers a RAS that provides high-speed wide-area reactive support in the BPA area.  The controls have proved effective for varying system conditions and topologies, and maintain stability for low probability, high consequence contingencies generally dismissed in today's deterministic planning studies. With investments being made in synchrophasor technology, the path of innovation has been laid; it's a matter of where it goes.  The goal of this research is to present simple, yet highly effective solutions to problems.  Doing so, the momentum behind synchrophasors can continue to build upon itself as it matures industry-wide. / Ph. D.
64

INTERNET OF THINGS SYSTEMS SECURITY: BENCHMARKING AND PROTECTION

Naif S Almakhdhub (8810120) 07 May 2020 (has links)
<div><p>Internet of Things (IoT) systems running on Microcontrollers (MCUS) have become a prominent target of remote attacks. Although deployed in security and safety critical domains, such systems lack basic mitigations against control-flow hijacking attacks. Attacks against IoT systems already enabled malicious takeover of smartphones, vehicles, unmanned aerial vehicles, and industrial control systems.</p></div><div><p> </p><div><p>The thesis introduces a systemic analysis of previous defense mitigations to secure IoT systems. Building off this systematization, we identify two main issues in IoT systems security. First, efforts to protect IoT systems are hindered by the lack of realistic benchmarks and evaluation frameworks. Second, existing solutions to protect from control-flow hijacking on the return edge are either impractical or have limited security guarantees. This thesis addresses these issues using two approaches. </p></div><div><p> </p></div><div><p>First, we present BenchIoT, a benchmark suite of five realistic IoT applications and an evaluation framework that enables automated and extensible evaluation of 14 metrics covering security, performance, memory usage, and energy. BenchIoT enables evaluating and comparing security mechanisms. Using BenchIoT, we show that even if two security mechanisms have similarly modest runtime overhead, one can have undesired consequences on security such as a large portion of privileged user execution.</p></div><div><p> </p></div><div><p>Second, we introduce Return Address Integrity (RAI), a novel security mechanism to prevent all control-flow hijacking attacks targeting return edges, without requiring special hardware. We design and implement μRAI to enforce the RAI property. Our results show μRAI has a low runtime overhead of 0.1% on average, and therefore is a</p></div><div><p>practical solution for IoT systems. </p></div><div><p> </p></div><div><p>This thesis enables measuring the security IoT systems through standardized benchmarks and metrics. Using static analysis and runtime monitors, it prevents control-flow hijacking attacks on return edges with low runtime overhead. Combined, this thesis advances the state-of-the-art of protecting IoT systems and benchmarking its security.</p></div></div>
65

Parametric sensitivity study for wind power trading through stochastic reserve and energy market optimization

Menin, Michel January 2015 (has links)
Trading optimal wind power in energy and regulation market offers possibil-ities for increasing revenues as well as impacting security of the system in apositive way[33]. The bidding in both energy and regulation markets can bedone through stochastic optimization process of both markets.Stochastic optimization can be possible once the probabilistic forecst is avail-able through ensemble forecast methodology. For stochastic optimization, thepost-processing of the ensembles to generate quantiles that will be used in op-timization can be accomplished by employing different methodology. In thisstudy, we will concentrate on the impact of post-processing of ensembles onthe stochastic optimization.Generation of quantiles needed for stochastic optimization used herein formarket optimization will be the main focus of the investigation. The impactof price ratios between energy and reserve market will be also investigated toanalyse the impact of said ratios on the revenues. Furthermore this analysiswill be performed for both US and Swedish markets.
66

On Reliability Methods Quantifying Risks to Transfer Capability in Electric Power Transmission Systems

Setréus, Johan January 2009 (has links)
<p><p>In the operation, planning and design of the transmission system it is of greatest concern to quantify the reliability security margin to unwanted conditions. The deterministic N-1 criterion has traditionally provided this security margin to reduce the consequences of severe conditions such as widespread blackouts. However, a deterministic criterion does not include the likelihood of different outage events. Moreover, experience from blackouts shows, e.g. in Sweden-Denmark September 2003, that the outages were not captured by the N-1 criterion. The question addressed in this thesis is how this system security margin can be quantified with probabilistic methods. A quantitative measure provides one valuable input to the decision-making process of selecting e.g. system expansions alternatives and maintenance actions in the planning and design phases. It is also beneficial for the operators in the control room to assess the associated security margin of existing and future network conditions.</p><p>This thesis presents a method that assesses each component's risk to an insufficient transfer capability in the transmission system. This shows on each component's importance to the system security margin. It provides a systematic analysis and ranking of outage events' risk of overloading critical transfer sections (CTS) in the system. The severity of each critical event is quantified in a risk index based on the likelihood of the event and the consequence of the section's transmission capacity. This enables a comparison of the risk of a frequent outage event with small CTS consequences, with a rare event with large consequences.</p><p>The developed approach has been applied for the generally known Roy Billinton Test System (RBTS). The result shows that the ranking of the components is highly dependent on the substation modelling and the studied system load level.</p><p>With the restriction of only evaluating the risks to the transfer capability in a few CTSs, the method provides a quantitative ranking of the potential risks to the system security margin at different load levels. Consequently, the developed reliability based approach provides information which could improve the deterministic criterion for transmission system planning.</p></p>
67

DIVERGENCE IN STAKEHOLDER PERCEPTIONS OF SECURITY POLICIES: A REPGRID ANALYSIS FOR NORM-RULE COMPLIANCE

Almusharraf, Ahlam 01 January 2016 (has links)
Many organizations have a problem with synchronizing individual values regarding information security with expectations set by the relevant security policy. Such discordance leads to failure in compliance or simply subversion of existing or imposed controls. The problem of the mismatch in understanding the security policies amongst individuals in an organization has devastating effect on security of the organization. Different individuals hold different understanding and knowledge about IS security, which is reflected on IS security policies design and practice (Vaast, 2007). Albrecthsen and Hovdena (2009) argue that users and managers practice IS security differently because they have different rationalities. This difference in rationalities may reflect the mismatch between the security policies and individuals’ values. In this research, we argue that occurrence of security breach can change individuals’ values in light of security policy of organization. These changes in the values can be reflected on the compliance between individuals’ norms and security rules and standards. Indeed, organizations need to guarantee the compliance between security policy and values of their employees. Thus, they can alleviate or prevent violations of security of organization. However, it is difficult to find a common method that all organizations can adopt to guarantee the synch between security rules and individuals’ norms. The main aim of this research is to investigate how people perceive information security policy and how their perceptions change in response to security breaches. Besides, this research aims to investigate the relationship between individuals’ values and security policy. Thus, organizations can have the intended level of compliance between individual norms and security rules and standards. With the aid of the Repertory Grid technique, this research examines how a security breach shapes people’s values with respect to security policy of an organization. To conduct the argument, this research offers an assessment mechanism that aids the organization to evaluate employees’ values in regard to security policy. Based on that evaluation, the organization can develop a proper mechanism to guarantee compliance between individuals’ norms and security rules. The results of this research show that employees in an organization hold different perceptions regarding the security policy. These perceptions change in response to security incident. This change in perceptions dose not necessarily result in better compliance with the security policy. Factors like the type of breach and people’s experience can affect the amount of change in the perceptions. Contributions, implications, and directions for future research of this study will be discussed.
68

Informationsäkerhet vid användning av SaaS : En studie om vilka aspekter som påverkar om informationsäkerheten höjs vid användning av Saas / Informations system security when using SaaS : A study of wich aspects affecting information system security when using SaaS

Åman, Petter January 2019 (has links)
I den tidiga IT-historien utgick data från att endast kunna angripas genom att befinna sig på fysisk plats för att kunna genomföra ett intrång och tillförskaffa sig data eller information. I äldre actionfilmer syns ofta någon rysk eller amerikansk spion som överför data från en fysisk dator till en lika fysisk disk. I takt med den ökade globaliseringen finns också ett ökat behov av tillgång till data och information på olika platser samt på olika sätt. För att tillfredsställa ett ökande behov av tillgänglighet och rörlighet har IT-världen fått skapa nya lösningar vilka uppfyller det behovet. Första steget var i och med införandet av internet och numera med nya olika molnlösningar tillgängliga för företag, privatpersoner och även angripare via internet. Moderna tekniker frambringar också i princip alltid nya risker och hot. Där det tidigare i mänskligheten användes lås för dörrar, måste nu beaktning tas där vilken typ av kryptering, virusskydd och andra åtgärder krävs för att skydda privat information. Cloud Computing och användningen av molntjänster som Software as a Service (SaaS), Plattform as a Service (PaaS) och Infrastructure as a Service (IaaS) fortsätter att öka vilket kan bidrar med många fördelar för företag (Balco, Drahošová &amp; Law, 2017; Basishtha &amp; Boruah, 2013; SCB, 2018; Sultan, 2011; Shahzad, 2014). Dock ger inte en flytt av data, från marken upp till molnet, en garanti för säkerhet eftersom molnets tillgänglighet och förflyttning av data utanför företagets gränser ställer frågor kring informationssäkerheten och kommer med många utmaningar samt risker (Kavitha &amp; Subashini, 2011; Dorey &amp; Leite, 2011). I och med utökad globalitet borde det väl vara passande att data lagras på olika platser i världen. Men hur säkert är det egentligen när ett företag baserat i exempelvis Finland har viktig data lagrad på andra sidan jordklotet? Eftersom ”Molnet” fortsätter att öka finns ett behov att undersöka hur, var och när användning av molnet kan bidra till att öka informationssäkerheten samt även varför och under vilka omständigheter. Studien kommer fokusera på användningen kring informationssäkerheten inom SaaS och vilka aspekter som påverkar om företag kan tillförskaffa ökad informationssäkerhet. SaaS har valts ut då molntjänsten är mest frekvent förekommen inom företag. Studiens rapport är uppbyggd på följande sätt: kapitel två tar upp relevanta begrepp samt bakgrund till ämnet. Därefter i kapitel tre beskrivs problemområdet samt rapportens syfte och frågeställning. I kapitel fyra presenteras studiens vetenskapliga metod vilken har använts för att samla in och analysera data. I kapitel fem presenteras analysen av arbetet vilket har lett fram till kapitel sex slutmodell. Slutligen följer en diskussion kring studien.
69

FEASIBILITY STUDY USING BLOCKCHAIN TO IMPLEMENT PROOF OF LOCATION

Kristina D. Lister-Gruesbeck (5930723) 17 January 2019 (has links)
The purpose of this thesis is to determine the feasibility of using blockchain to implement proof of location. There has been an increasing demand for a way to create a validated proof of location that is economical, and easy to deploy as well as portable. There are several reasons for an increased demand in this technology including the ever-increasing number of mobile gamers that have been able to spoof their location successfully, the increasing number of on demand package shipments from companies such as Amazon, and the desire to reduce the occurrence of medical errors as well as holding hospitals accountable for their errors. Additional reasons that this technology is gaining popularity and increasing in demand is due the continually increasing number of lost baggage claims that airlines are receiving, as well as insurance companies desire to reduce the number of fraud cases that are related to high-value goods as well as increasing the probability of their recovery. Within the past year, there has been an extensive amount of research as well as work that has been completed to create an irrefutable method of location verification, which will permit a user to be able to create time-stamped documentation validating that they were at a particular location at a certain day and time. Additionally, the user is then permitted to release the information at a later date and time that is convenient for them. This research was completed using a Raspberry Pi 3B, a Raspberry Pi 3B+, two virtual Raspberry Pi’s as well as two virtual servers in which the goal was to download, and setup either Ethereum and/or Tendermint Blockchain on each piece of equipment. After completely synchronizing the blockchain it be used to store the verified location data that been time-stamped. There was a variety of issues that were encountered during the setup and installation of the blockchains on the equipment including overclocking processors, which negatively affected the computational abilities of the devices as well as causing overheating and surges in voltage as well as a variety of software and hardware incompatibilities. These issues when looked at individually appear to not have much of an impact on the results of this research but when combined together it is obvious that they reduced the results that could be obtained. In conclusion, the combination of hardware and software issues when combined with the temperature and voltage issues that were due to the overheating of the processor resulted in several insurmountable issues that could not be overcome. There are several recommendations for continuing this work including presyncing the blockchain using a computer, using a device that has more functionality and computational abilities, connecting a cooling device such as a fan or adding a heat sink, increasing the available power supply, utilizing an externally power hard drive for data storage, recreate this research with the goal in mind of determining what process or application was causing the high processor usage, or creating a distributed system that utilizes both physical and virtual equipment to reduce the amount of work on one type of device.
70

BUILDING FAST, SCALABLE, LOW-COST, AND SAFE RDMA SYSTEMS IN DATACENTERS

Shin-yeh Tsai (7027667) 16 October 2019 (has links)
<div>Remote Direct Memory Access, or RDMA, is a technology that allows one computer server to direct access the memory of another server without involving its CPU. Compared with traditional network technologies, RDMA offers several benefits including low latency, high throughput, and low CPU utilization. These features are especially attractive to datacenters, and because of this, datacenters have started to adopt RDMA in production scale in recent years.</div><div>However, RDMA was designed for confined, single-tenant, High-Performance-Computing (HPC) environments. Many of its design choices do not fit datacenters well, and it cannot be readily used by datacenter applications. To use RDMA, current datacenter applications have to build customized software stacks and fine-tune their performance. In addition, RDMA offers limited scalability and does not have good support for resource sharing or protection across different applications.</div><div>This dissertation sets out to seek solutions that can solve issues of RDMA in a systematic way and makes it more suitable for a wide range of datacenter applications.</div><div>Our first task is to make RDMA more scalable, easier to use, and have better support for safe resource sharing in datacenters. For this purpose, we propose to add an indirection layer on top of native RDMA to virtualize its low-level abstraction into a high-level one. This indirection layer safely manages RDMA resources for different datacenter applications and also provide a means for better scalability.</div><div>After making RDMA more suitable for datacenter environments, our next task is to build applications that can exploit all the benefits from (our improved) RDMA. We designed a set of systems that store data in remote persistent memory and let client machines access these data through pure one-sided RDMA communication. These systems lower monetary and energy cost compared to traditional datacenter data stores (because no processor is needed at remote persistent memory), while achieving good performance and reliability.</div><div>Our final task focuses on a completely different and so far largely overlooked one — security implications of RDMA. We discovered several key vulnerabilities in the one-sided communication pattern and in RDMA hardware. We exploited one of them to create a novel set of remote side-channel attacks, which we are able to launch on a widely used RDMA system with real RDMA hardware.</div><div>This dissertation is one of the initial efforts in making RDMA more suitable for datacenter environments from scalability, usability, cost, and security aspects. We hope that the systems we built as well as the lessons we learned can be helpful to future networking and systems researchers and practitioners.</div>

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