Telehealth is an online health care system that is extensively used in the current pandemic situation. Our proposed technique is considered a fog computing-based attack detection architecture to protect IoT Telehealth Networks. As for IoT Telehealth Networks, the sensor/actuator edge devices are considered the weakest link in the IoT system and are obvious targets of attacks such as botnet attacks. In this thesis, we introduce a novel framework that employs several machine learning and data analysis techniques to detect those attacks. We evaluate the effectiveness of the proposed framework using two publicly available datasets from real-world scenarios. These datasets contain a variety of attacks with different characteristics. The robustness of the proposed framework and its ability, to detect and distinguish between the existing IoT attacks that are tested by combining the two datasets for cross-evaluation. This combination is based on a novel technique for generating supplementary data instances, which employs GAN (generative adversarial networks) for data augmentation and to ensure that the number of samples and features are balanced. / Graduate

Security of communications is a major requirement for Mobile Adhoc NETworks(MANETs) since they use wireless channel for communications which can be easily tapped, and physical capture of MANET nodes is also quite easy. From the point of view of providing security in MANETs, there are basically two types of MANETs, viz., authoritarian MANETs, in which there exist one or more authorities who decide the members of the network, and self-organized MANETs, in which there is no such authority. Ensuring security of communications in the MANETs is a challenging task due to the resource constraints and infrastructure-less nature of these networks, and the limited physical security of MANET nodes. Attacks on security in a MANET can be launched by either the external attackers which are not legitimate members of the MANET or the internal attackers which are compromised members of the MANET and which can hold some valid security credentials or both. Key management and authentication protocols(KM-APs)play an important role in preventing the external attackers in a MANET. However, in order to prevent the internal attackers, an intrusion detection system(IDS) is essential. The routing protocols running in the network layer of a MANET are most vulnerable to the internal attackers, especially to the attackers which launch packet dropping attack during data packet forwarding in the MANET. For an authoritarian MANET, an arbitrated KM-AP protocol is perfectly suitable, where trusts among network members are coordinated by a trusted authority. Moreover, due to the resource constraints of a MANET, symmetric key management protocols are more efficient than the public key management protocols in authoritarian MANETs. The existing arbitrated symmetric key management protocols in MANETs, that do not use any authentication server inside the network are susceptible to identity impersonation attack during shared key establishments. On the other hand, the existing server coordinated arbitrated symmetric key management protocols in MANETs do not differentiate the role of a membership granting server(MGS) from the role of an authentication server, and so both are kept inside the network. However, keeping the MGS outside the network is more secure than keeping it inside the network for a MANET. Also, the use of a single authentication server inside the network cannot ensure robustness against authentication server compromise. In self-organized MANETs, public key management is more preferable over symmetric key management, since the distribution of public keys does not require a pre-established secure channel. The main problem for the existing self-organized public key management protocols in MANETs is associated with the use of large size certificate chains. Besides, the proactive certificate chaining based approaches require each member of a MANET to maintain an updated view of the trust graph of the entire network, which is highly resource consuming. Maintaining a hierarchy of trust relationships among members of a MANET is also problematic for the same reason. Evaluating the strength of different alternative trust chains and restricting the length of a trust chain used for public key verification is also important for enhancing the security of self-organized public key management protocols. The existing network layer IDS protocols in MANETs that try to defend against packet dropping attack use either a reputation based or an incentive based approach. The reputation based approaches are more effective against malicious principals than the incentive based approaches. The major problem associated with the existing reputation based IDS protocols is that they do not consider the protocol soundness issue in their design objectives. Besides, most of the existing protocols incorporate no mechanism to fight against colluding principals. Also, an IDS protocol in MANETs should incorporate some secure and efficient mechanism to authenticate the control packets used by it. In order to mitigate the above mentioned problems in MANETs, we have proposed new models and designed novel security protocols in this thesis that can enhance the security of communications in MANETs at lesser or comparable cost. First, in order to perform security analysis of KM-AP protocols, we have extended the well known strand space verification model to overcome some of its limitations. Second, we have proposed a model for the study of membership of principals in MANETs with a view to utilize the concept for analyzing the applicability and the performance of KM-AP protocols in different types of MANETs. Third and fourth, we have proposed two novel KM-AP protocols, SEAP and CLPKM, applicable in two different types of MANET scenarios. The SEAP protocol is an arbitrated symmetric key management protocol designed to work in an authoritarian MANET, whereas the CLPKM protocol is a self-organized public key management protocol designed for self-organized MANETs. Fifth, we have designed a novel reputation based network layer IDS protocol, named EVAACK protocol, for the detection of packet dropping misbehavior in MANETs. All of the three proposed protocols try to overcome the limitations of the existing approaches in their respective categories. We have provided rigorous mathematical proofs for the security properties of the proposed protocols. Performance of the proposed protocols have been compared with those of the other existing similar approaches using simulations in the QualNet simulator. In addition, we have also implemented the proposed SEAP and CLPKM protocols on a real MANET test bed to test their performances in real environments. The analytical, simulation and experimentation results confirm the effectiveness of the proposed schemes.

A Mobile Ad Hoc Network (MANETs) is a collection of wireless hosts that can be rapidly deployed as a multi hop packet radio network without the aid of any established infrastructure or centralized administration. Such networks can be used to enable next generation of battlefield applications envisioned by the military, including situation awareness systems for maneuvering war fighters, and remotely deployed unmanned microsensor networks. Ad Hoc networks can also provide solutions for civilian applications such as disaster recovery and message exchanges among safety and security personnel involved in rescue missions. Existing solutions for wired network Intrusion Detection Systems (IDSs) do not suit wireless Ad Hoc networks. To utilize either misuse detection or anomaly detection to monitor any possible compromises, the IDS must be able to distinguish normal from anomaly activities. To enable intrusion detection in wireless Ad Hoc networks, the research problems are: • How to efficiently collect normal and anomaly patterns of Ad Hoc networks? The lifetime of the hosts is short and Ad Hoc networks do not have traffic concentration points (router, switch). • How to detect anomalies? The loss could be caused by host movement instead of attacks. Unexpectedly long delay could be caused by unreliable channel instead of malicious discard. In this thesis, we have proposed a novel architecture that uses specification based intrusion detection techniques to detect active attacks against the routing protocols of mobile Ad Hoc networks. Our work analyzes some of the vulnerabilities and discuss the attacks against the AODV protocol. Our approach involves the use of an FSM (Finite State Machine) for specifying the AODV routing behavior and the distributed network monitors for detecting the sequence number attack. Our method can detect most of the bad nodes with low false positive rate and the packet delivery ratio can also be increased with high detection rate. For packet dropping attack, we present a distributed technique to detect this attack in wireless Ad Hoc networks. A bad node can forward packets but in fact it fails to do so. In our technique, every node in the network will check the neighboring nodes to detect if any of them fail to forward the packets. Our technique can detect most of the bad nodes with low false positive rate and the packet delivery ratio can also be increased. The proposed solution can be applied to identify multiple malicious nodes cooperating with each other in MANETs and discover secure routes from source to destination by avoiding malicious nodes acting in cooperation. Our technique will detect the sequence number and Packet Dropping attacks in real time within its radio range with no extra overhead. For resource consumption attack, the proposed scheme incurs no extra overhead, as it makes minimal modifications to the existing data structures and functions related to bad listing a node in the existing version of pure AODV. The proposed scheme is more efficient in terms of the resultant routes established, resource reservations, and computational complexity. If multiple malicious nodes collaborate, they in turn will be restricted and isolated by their neighbors, because they monitor and exercise control over forwarding RREQs by nodes. Hence, the scheme successfully prevents Distributed attacks. The proposed scheme shifts the responsibility of monitoring this parameter to the node's neighbor, ensuring compliance of this restriction. This technique solves all of the problems caused due to unnecessary RREQs from a compromised node. Instead of self-control, the control exercised by a node's neighbor results in preventing this attack. Experiments show that the tool provides effective intrusion detection functionality while using only a limited amount of resources. The loop freedom property has been reduced to an invariant on pairs of nodes. Each node decides & transmits its decision to a control center. Robustness to Threats, Robustness to nodes destruction: Loss of Performance (in terms of ratio) is least for Distributed Option and highest for Centralized Option and Robustness to observations deletion. All the proposed schemes were analyzed and tested under different topologies and conditions with varying number of nodes .The proposed algorithms for improving the robustness of the wireless Ad Hoc networks using AODV protocol against Packet Dropping Attack, Sequence Number attack and resource consumption attack have been simulated for an illustrative network of about 30 nodes. Our experiments have shown that the pattern extracted through simulation can be used to detect attacks effectively. The patterns could also be applied to detect similar attacks on other protocols.