Biblio
The design of attacks for cyber physical systems is critical to assess CPS resilience at design time and run-time, and to generate rich datasets from testbeds for research. Attacks against cyber physical systems distinguish themselves from IT attacks in that the main objective is to harm the physical system. Therefore, both cyber and physical system knowledge are needed to design such attacks. The current practice to generate attacks either focuses on the cyber part of the system using IT cyber security existing body of knowledge, or uses heuristics to inject attacks that could potentially harm the physical process. In this paper, we present a systematic approach to automatically generate integrity attacks from the CPS safety and control specifications, without knowledge of the physical system or its dynamics. The generated attacks violate the system operational and safety requirements, hence present a genuine test for system resilience. We present an algorithm to automate the malware payload development. Several examples are given throughout the paper to illustrate the proposed approach.
Distributed Denial of Service (DDoS) attacks became a true threat to network infrastructure. DDoS attacks are capable of inflicting major disruption to the information communication technology infrastructure. DDoS attacks aim to paralyze networks by overloading servers, network links, and network devices with illegitimate traffic. Therefore, it is important to detect and mitigate DDoS attacks to reduce the impact of DDoS attacks. In traditional networks, the hardware and software to detect and mitigate DDoS attacks are expensive and difficult to deploy. Software-Defined Network (SDN) is a new paradigm in network architecture by separating the control plane and data plane, thereby increasing scalability, flexibility, control, and network management. Therefore, SDN can dynamically change DDoS traffic forwarding rules and improve network security. In this study, a DDoS attack detection and mitigation system was built on the SDN architecture using the random forest machine-learning algorithm. The random forest algorithm will classify normal and attack packets based on flow entries. If packets are classified as a DDoS attack, it will be mitigated by adding flow rules to the switch. Based on tests that have been done, the detection system can detect DDoS attacks with an average accuracy of 98.38% and an average detection time of 36 ms. Then the mitigation system can mitigate DDoS attacks with an average mitigation time of 1179 ms and can reduce the average number of attack packets that enter the victim host by 15672 packets and can reduce the average number of CPU usage on the controller by 44,9%.
Physical layer authentication (PLA) has recently been discussed in the context of URLLC due to its low complexity and low overhead. Nevertheless, these schemes also introduce additional sources of error through missed detections and false alarms. The trade-offs of these characteristics are strongly dependent on the deployment scenario as well as the processing architecture. Thus, considering a feature-based PLA scheme utilizing channel-state information at multiple distributed radio-heads, we study these trade-offs analytically. We model and analyze different scenarios of centralized and decentralized decision-making and decoding, as well as the impacts of a single-antenna attacker launching a Sybil attack. Based on stochastic network calculus, we provide worst-case performance bounds on the system-level delay for the considered distributed scenarios under a Sybil attack. Results show that the arrival-rate capacity for a given latency deadline is increased for the distributed scenarios. For a clustered sensor deployment, we find that the distributed approach provides 23% higher capacity when compared to the centralized scenario.
Federated learning (FL) allows to train a massive amount of data privately due to its decentralized structure. Stochastic gradient descent (SGD) is commonly used for FL due to its good empirical performance, but sensitive user information can still be inferred from weight updates shared during FL iterations. We consider Gaussian mechanisms to preserve local differential privacy (LDP) of user data in the FL model with SGD. The trade-offs between user privacy, global utility, and transmission rate are proved by defining appropriate metrics for FL with LDP. Compared to existing results, the query sensitivity used in LDP is defined as a variable, and a tighter privacy accounting method is applied. The proposed utility bound allows heterogeneous parameters over all users. Our bounds characterize how much utility decreases and transmission rate increases if a stronger privacy regime is targeted. Furthermore, given a target privacy level, our results guarantee a significantly larger utility and a smaller transmission rate as compared to existing privacy accounting methods.
Smart grid monitoring, automation and control will completely rely on PMU based sensor data soon. Accordingly, a high throughput, low latency Information and Communication Technology (ICT) infrastructure should be opted in this regard. Due to the low cost, low power profile, dynamic nature, improved accuracy and scalability, wireless sensor networks (WSNs) can be a good choice. Yet, the efficiency of a WSN depends a lot on the network design and the routing technique. In this paper a new design of the ICT network for smart grid using WSN is proposed. In order to understand the interactions between different entities, detect their operational levels, design the routing scheme and identify false data injection by particular ICT entities, a new model of interdependency called the Multi State Implicative Interdependency Model (MSIIM) is proposed in this paper, which is an updated version of the Modified Implicative Interdependency Model (MIIM) [1]. MSIIM considers the data dependency and operational accuracy of entities together with structural and functional dependencies between them. A multi-path secure routing technique is also proposed in this paper which relies on the MSIIM model for its functioning. Simulation results prove that MSIIM based False Data Injection (FDI) detection and mitigation works better and faster than existing methods.
With the emergence of computationally intensive and delay sensitive applications, mobile edge computing(MEC) has become more and more popular. Simultaneously, MEC paradigm is faced with security challenges, the most harmful of which is DDoS attack. In this paper, we focus on the resource orchestration algorithm in MEC scenario to mitigate DDoS attack. Most of existing works on resource orchestration algorithm barely take into account DDoS attack. Moreover, they assume that MEC nodes are unselfish, while in practice MEC nodes are selfish and try to maximize their individual utility only, as they usually belong to different network operators. To solve such problems, we propose a price-based resource orchestration algorithm(PROA) using game theory and convex optimization, which aims at mitigating DDoS attack while maximizing the utility of each participant. Pricing resources to simulate market mechanisms, which is national to make rational decisions for all participants. Finally, we conduct experiment using Matlab and show that the proposed PROA can effectively mitigate DDoS attack on the attacked MEC node.
As millions of IoT devices are interconnected together for better communication and computation, compromising even a single device opens a gateway for the adversary to access the network leading to an epidemic. It is pivotal to detect any malicious activity on a device and mitigate the threat. Among multiple feasible security threats, malware (malicious applications) poses a serious risk to modern IoT networks. A wide range of malware can replicate itself and propagate through the network via the underlying connectivity in the IoT networks making the malware epidemic inevitable. There exist several techniques ranging from heuristics to game-theory based technique to model the malware propagation and minimize the impact on the overall network. The state-of-the-art game-theory based approaches solely focus either on the network performance or the malware confinement but does not optimize both simultaneously. In this paper, we propose a throughput-aware game theory-based end-to-end IoT network security framework to confine the malware epidemic while preserving the overall network performance. We propose a two-player game with one player being the attacker and other being the defender. Each player has three different strategies and each strategy leads to a certain gain to that player with an associated cost. A tailored min-max algorithm was introduced to solve the game. We have evaluated our strategy on a 500 node network for different classes of malware and compare with existing state-of-the-art heuristic and game theory-based solutions.
It has been a hot research topic to detect and mitigate Distributed Denial-of-Service (DDoS) attacks due to the significant increase of serious threat of such attacks. The rapid growth of Internet of Things (IoT) has intensified this trend, e.g. the Mirai botnet and variants. To address this issue, a light-weight DDoS mitigation mechanism was presented. In the proposed scheme, flooding attacks are detected by stochastic queue allocation which can be executed with widespread and inexpensive commercial products at a network edge. However, the detection process is delayed when the number of incoming flows is large because of the randomness of queue allocation. Thus, in this paper we propose an efficient queue allocation algorithm for rapid DDoS mitigation using limited resources. The idea behind the proposed scheme is to avoid duplicate allocation by decreasing the randomness of the existing scheme. The performance of the proposed scheme was confirmed via theoretical analysis and computer simulation. As a result, it was confirmed that malicious flows are efficiently detected and discarded with the proposed algorithm.
This paper studies the secure computation offloading for multi-user multi-server mobile edge computing (MEC)-enabled internet of things (IoT). A novel jamming signal scheme is designed to interfere with the decoding process at the Eve, but not impair the uplink task offloading from users to APs. Considering offloading latency and secrecy constraints, this paper studies the joint optimization of communication and computation resource allocation, as well as partial offloading ratio to maximize the total secrecy offloading data (TSOD) during the whole offloading process. The considered problem is nonconvex, and we resort to block coordinate descent (BCD) method to decompose it into three subproblems. An efficient iterative algorithm is proposed to achieve a locally optimal solution to power allocation subproblem. Then the optimal computation resource allocation and offloading ratio are derived in closed forms. Simulation results demonstrate that the proposed algorithm converges fast and achieves higher TSOD than some heuristics.
Although many digital signature algorithms are available nowadays, the speed of signing and/or verifying a digital signature is crucial for different applications. Some algorithms are fast for signing but slow for verification, but others are the inverse. Research efforts for an algorithm being fast in both signing and verification is essential. The traditional GOST algorithm has the shortest signing time but longest verification time compared with other DSA algorithms. Hence an improvement in its signature verification time is sought in this work. A modified GOST digital signature algorithm variant is developed improve the signature verification speed by reducing the computation complexity as well as benefiting from its efficient signing speed. The obtained signature verification execution speed for this variant was 1.5 time faster than that for the original algorithm. Obviously, all parameters' values used, such as public and private key, random numbers, etc. for both signing and verification processes were the same. Hence, this algorithm variant will prove suitable for applications that require short time for both, signing and verification processes. Keywords— Discrete Algorithms, Authentication, Digital Signature Algorithms DSA, GOST, Data Integrity



