Network anomaly detection is an important and dynamic research area. Many network intrusion detection methods and systems (NIDS) have been proposed in the literature. In this paper, we provide a structured and comprehensive overview of various facets of network anomaly detection so that a researcher can become quickly familiar with every aspect of network anomaly detection. We present attacks normally encountered by network intrusion detection systems. We categorize existing network anomaly detection methods and systems based on the underlying computational techniques used. Within this framework, we briefly describe and compare a large number of network anomaly detection methods and systems. In addition, we also discuss tools that can be used by network defenders and datasets that researchers in network anomaly detection can use. We also highlight research directions in network anomaly detection.

Network Anomaly Detection: Methods, Systems and Tools

Due to the broadcast nature of radio propagation, the wireless air interface is open and accessible to both authorized and illegitimate users. This completely differs from a wired network, where communicating devices are physically connected through cables and a node without direct association is unable to access the network for illicit activities. The open communications environment makes wireless transmissions more vulnerable than wired communications to malicious attacks, including both the passive eavesdropping for data interception and the active jamming for disrupting legitimate transmissions. Therefore, this paper is motivated to examine the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity, and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state of the art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. Several physical-layer security techniques are reviewed and compared, including information-theoretic security, artificial-noise-aided security, security-oriented beamforming, diversity-assisted security, and physical-layer key generation approaches. Since a jammer emitting radio signals can readily interfere with the legitimate wireless users, we also introduce the family of various jamming attacks and their countermeasures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer, and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

/pdf/a-survey-on-wireless-security-technical-challenges-recent-3uamoalvot.pdf

A Survey on Wireless Security: Technical Challenges, Recent Advances, and Future Trends

The use of unmanned aerial vehicles (UAVs) is growing rapidly across many civil application domains, including real-time monitoring, providing wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are the next big revolution in the UAV technology promising to provide new opportunities in different applications, especially in civil infrastructure in terms of reduced risks and lower cost. Civil infrastructure is expected to dominate more than $45 Billion market value of UAV usage. In this paper, we present UAV civil applications and their challenges. We also discuss the current research trends and provide future insights for potential UAV uses. Furthermore, we present the key challenges for UAV civil applications, including charging challenges, collision avoidance and swarming challenges, and networking and security-related challenges. Based on our review of the recent literature, we discuss open research challenges and draw high-level insights on how these challenges might be approached.

Unmanned Aerial Vehicles: A Survey on Civil Applications and Key Research Challenges

This paper examines the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state-of-the-art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. We also introduce the family of various jamming attacks and their counter-measures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

/pdf/a-survey-on-wireless-security-technical-challenges-recent-k705wofne7.pdf

A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends

Smart grid is a promising power delivery infrastructure integrated with communication and information technologies. Its bi-directional communication and electricity flow enable both utilities and customers to monitor, predict, and manage energy usage. It also advances energy and environmental sustainability through the integration of vast distributed energy resources. Deploying such a green electric system has enormous and far-reaching economic and social benefits. Nevertheless, increased interconnection and integration also introduce cyber-vulnerabilities into the grid. Failure to address these problems will hinder the modernization of the existing power system. In order to build a reliable smart grid, an overview of relevant cyber security and privacy issues is presented. Based on current literatures, several potential research fields are discussed at the end of this paper.

https://repository.um.edu.mo/bitstream/10692/2883/3/Liu-2012-Cyber-security-and-privacy-issues-i.pdf

Cyber Security and Privacy Issues in Smart Grids

There has been some work done in studying the behavior of TCP/IP's Van Jacobson header compression (VJHC) over high bit-error-rate (BER) and long delay channels such as in the space environment However, most studies have been done based on discussing the definitions and methodologies of the scheme There are hardly any experimental results seen in support of these discussions This paper discusses an experimental examination of the VJHC behavior in a lossy GEO-satellite environment, simulated using a test-bed The experimental results show that VJHC causes go-back-n retransmission behavior When a single packet is corrupted or lost, all packets arriving after the lost or corrupted packet, up to one bandwidth-delay product's worth, are lost and need to be retransmitted This results in performance degradation in an environment with a very high BER (around 10/sup -5/) and long link delay In comparison, when VJHC is disabled, only the corrupted or lost packets are retransmitted, avoiding unnecessary retransmissions This suggests that it is better to disable TCP/IP's VJHC over very lossy channels

An experimental study of TCP/IP's Van Jacobson header compression behavior in lossy space environment

Cognitive radio has potential to improve spectrum efficiency in future wireless multimedia communications. There exist various performance problems in the dynamic spectrum resource management, frequency sense and utilization for cognitive radio. In this paper, a novel frequency sense solution based on the double-station cooperation and multi-hop tracing localization is proposed to resolve the hidden and exposed problems in spectrum resource management. In specific, the solution is proposed to improve reliability and efficiency of frequency sense and increase the utilization of spectrum. With this solution, a secondary user can obtain more accurate primary user's location by an improved centroid localization algorithm cooperated with a known position user. The tracing localization accuracy is also analyzed. Simulation results show that the proposed solution significantly improves the performance while location accuracy is still within controllable range after multiple tracing hops.

A Novel Frequency Sense Solution for Cognitive Radio Based on Tracing Localization

Bundle Protocol is the main protocol of delay-/disruption-tolerant networking. Its store-and-forward mechanism and custody transfer option enable it to provide reliable file delivery services in a stressed communications environment. A typical application of Bundle Protocol is for data delivery in a deep-space communication environment, which is characterized by an extremely long signal propagation delay. However, little work has been seen in performance of Bundle Protocol transmission in deep-space communications. In this article, we present an overview of file transfer operation and performance of Bundle Protocol over a relay-based deepspace communication infrastructure characterized by highly asymmetric channel rates based on file transfer experiments. An optimal Bundle Protocol bundle size for the best transmission performance is also under investigation in this article.

Bundle protocol for data delivery over highly asymmetric deep-space channels

The acknowledgement (ACK) strategy of the transmission control protocol (TCP) has been modified to improve its performance in asymmetric networks, like in the space communication environment. A general relationship between asymmetric channel ratio and optimal ACK frequency, to achieve maximal throughput, is not available. This paper studies optimal ACK frequency with respect to round-trip time (RTT) to achieve the maximum throughput over various asymmetric GEO-satellite links, using a test-bed, and builds a simple model for the relationship between optimal ACK frequency and asymmetric channel ratio.

Analysis of optimal ACK frequency over asymmetric GEO-space channels

Bundle protocol (BP) is the core protocol of delay/disruption-tolerant networking, which has been recognized as the only candidate networking technology that approaches the level of maturity required for deep-space mission communications. BP is intended to establish an overlay network for reliable data transfer over highly unreliable space links. A hybrid reliability strategy based on combining “proactive” retransmission and “reactive” retransmission of BP bundles is presented in this article as a means of achieving highly reliable file/data delivery in deep-space communication networks. Available electrical power on spacecraft is widely recognized as a scarce resource, especially for spacecraft in deep space where energy consumption is an important consideration for communications. In this article, the hybrid bundle retransmission approach is studied by means of a file transfer experiment over a PC-based testbed. The study focuses on variation in the transmission overhead and energy consumption of BP as a function of file size and retransmission timeout interval length.

Ruhai Wang

Papers

An experimental study of TCP/IP's Van Jacobson header compression behavior in lossy space environment

A Novel Frequency Sense Solution for Cognitive Radio Based on Tracing Localization

Bundle protocol for data delivery over highly asymmetric deep-space channels

Analysis of optimal ACK frequency over asymmetric GEO-space channels

Resource Consumption of a Hybrid Bundle Retransmission Approach on Deep-Space Communication Channels