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

Developed as the main protocol of delay/disruption-tolerant networking (DTN) for space, bundle protocol (BP) is intended to establish an overlay network for reliable data delivery in a heterogeneous networking environment. The effect of a link disruption on reliable data transmission of BP is currently under study. In this paper, a study of the effect of link disruption on BP's reliable data delivery in deep-space vehicle communications, from spatial and temporal perspectives, is presented employing both analytical and experimental methods. The effect is modeled in various transmission cases by considering the physical distance the bundle has traversed when the link disruption starts and ends, the duration of link disruption in time, and the physical span of the link disruption. The models are built to quantify the number of transmission attempts that fail due to link disruption, the total number of transmission attempts, bundle delivery time, and transmission goodput performance for successful bundle delivery in presence of a link disruption. The models are validated by realistic bundle delivery over a PC-based experimental testbed. The validation indicates that the analytical models predict the transmission performance of BP in presence of random link disruption in various aspects of successful bundle delivery.

A Study of Link Disruption on BP From Spatial and Temporal Perspectives in Deep-Space Vehicle Communications

Reliable data transmission mechanisms of bundle protocol (BP) are presently under development for delay/disruption-tolerant networking (DTN). In this paper, a new transmission approach is proposed for BP for highly reliable data delivery in deep-space communications in presence of unpredictable or random link disruption. The main idea of the proposed approach is to employ a joint use of the proactive retransmission mechanism and active retransmission mechanism during file transfer. The performance of the approach is analyzed in four different cases according to different starting times of link disruption. Analytical models are built to estimate the effect of link disruption on BP transmission with focus on the number of transmission attempts and the total file delivery time affected by the link disruption. The models are validated by the file transfer experiment over a PC-based testbed.

Reliable Proactive Retransmission of Bundle Protocol for Deep-Space Communications in Presence of Link Disruption

The Transmission Control Protocol (TCP) employs an acknowledgment (ACK) mechanism for reliable transfer of information. Selective acknowledgment (SACK) and negative acknowledgment (NAK) are well-known acknowledgment schemes in the current Internet. Selective negative acknowledgment (SNACK) is a novel acknowledgment scheme which integrates the capabilities of both SACK and NAK and has been developed for space Internet. It is expected to have a detailed description of the SNACK scheme with the support of some experimental results. The paper provides a full description of the novel SNACK scheme, comparing it with the widely used SACK scheme. The description is supported by some experimental data obtained from file transfer tests using a space-to-ground link simulation (SGLS) test-bed. Sampled experimental results show that SNACK has no negative effects on throughput at a low BER, but makes better utilization of channel bandwidth and achieves significantly higher throughput in error prone links, such as satellite and wireless channels.

A novel acknowledgment scheme for space Internet

The bundle protocol (BP) and Licklider transmission protocol (LTP) were developed to provide reliable and highly efficient data delivery over unreliable space vehicle communication channels. Some preliminary studies on cross-layer BP/LTP data block size in space vehicle communications have been done. However, the effect of data losses on the block has been ignored. Data loss caused by lossy space channels is one of the key features that characterize space vehicle communications, and therefore its effect cannot be left out. In this article, the cross-layer BP/LTP block size in space vehicle communications is studied with focus on its characterization and performance over lossy space channels. An analytical model is presented for calculating the minimum number of bundles that should be aggregated within an LTP block for transmission over a lossy channel so that the report segment (RS) delay imposed by highly asymmetric channel rates can be resolved. The model is validated by realistic file transfer experiments over an experimental testbed infrastructure and packet-level analysis of the results. The transmission performance of LTP with respect to variations of the aggregated block size, channel date rate and channel loss rate are discussed.

Ruhai Wang

Papers

A Study of Link Disruption on BP From Spatial and Temporal Perspectives in Deep-Space Vehicle Communications

Reliable Proactive Retransmission of Bundle Protocol for Deep-Space Communications in Presence of Link Disruption

A novel acknowledgment scheme for space Internet

A Study of Cross-Layer BP/LTP Data Block Size in Space Vehicle Communications Over Lossy and Highly Asymmetric Channels

Delay Tolerant Networking (DTN) Protocols for Space Communications.