João V. P. Gomes

Security issues in cloud environments: a survey

In the last few years, the appealing features of cloud computing have been fueling the integration of cloud environments in the industry, which has been consequently motivating the research on related technologies by both the industry and the academia. The possibility of paying-as-you-go mixed with an on-demand elastic operation is changing the enterprise computing model, shifting on-premises infrastructures to off-premises data centers, accessed over the Internet and managed by cloud hosting providers. Regardless of its advantages, the transition to this computing paradigm raises security concerns, which are the subject of several studies. Besides of the issues derived from Web technologies and the Internet, clouds introduce new issues that should be cleared out first in order to further allow the number of cloud deployments to increase. This paper surveys the works on cloud security issues, making a comprehensive review of the literature on the subject. It addresses several key topics, namely vulnerabilities, threats, and attacks, proposing a taxonomy for their classification. It also contains a thorough review of the main concepts concerning the security state of cloud environments and discusses several open research topics.

Detection and classification of peer-to-peer traffic: A survey

The emergence of new Internet paradigms has changed the common properties of network data, increasing the bandwidth consumption and balancing traffic in both directions. These facts raise important challenges, making it necessary to devise effective solutions for managing network traffic. Since traditional methods are rather ineffective and easily bypassed, particular attention has been paid to the development of new approaches for traffic classification. This article surveys the studies on peer-to-peer traffic detection and classification, making an extended review of the literature. Furthermore, it provides a comprehensive analysis of the concepts and strategies for network monitoring.

Analysis of Peer-to-Peer Traffic Using a Behavioural Method Based on Entropy

The increasing number of applications offering their services over peer-to-peer (P2P) platforms is changing the properties of the traffic within computer networks. Their massive use raises a few imperative challenges for network administrators and Internet service providers, regarding the quality of service and security of their networks. It such scenario, it is important to develop mechanisms to control and efficiently manage the P2P traffic and prepare the networks to support it, for which it is necessary to study the effect of P2P applications in the traffic of computer networks and to develop methodologies to characterise its behaviour. In this paper, the characteristics of the traffic generated by P2P applications are analysed from the behavioural point of view, and entropy is used to measure the heterogeneity embedded in the packet sizes. The results obtained show evident difference between P2P and non-P2P traffic, being the proposed approach applicable to real-time and high-speed networks with encrypted P2P traffic, where the existing methodologies are useless.

Cloud Security: State of the Art

Throughout the end of the first half and during the second half of the past century, advances in technology allowed scientists to develop computer systems. In the beginning, mostly between the forties and the sixties, single computers would fill large rooms with electronics that would consume as much power as several hundreds of modern desktop computers.

Source traffic analysis

Traffic modeling and simulation plays an important role in the area of Network Monitoring and Analysis, for it provides practitioners with efficient tools to evaluate the performance of networks and of their elements. This article focus on the traffic generated by a single source, providing an overview of what was done in the field and studying the statistical properties of the traffic produced by a personal computer, including analysis of the autocorrelation structure. Different distributions were fitted to the interarrival times, packet sizes, and byte count processes with the goal of singling out the ones most suitable for traffic generation.

Identification of Peer-to-Peer VoIP Sessions Using Entropy and Codec Properties

Voice over Internet Protocol (VoIP) applications based on peer-to-peer (P2P) communications have been experiencing considerable growth in terms of number of users. To overcome filtering policies or protect the privacy of their users, most of these applications implement mechanisms such as protocol obfuscation or payload encryption that avoid the inspection of their traffic, making it difficult to identify its nature. The incapacity to determine the application that is responsible for a certain flow raises challenges for the effective management of the network. In this paper, a new method for the identification of VoIP sessions is presented. The proposed mechanism classifies the flows, in real-time, based on the speech codec used in the session. To make the classification lightweight, the behavioral signatures for each analyzed codec were created using only the lengths of the packets. Unlike most previous approaches, the classifier does not use the lengths of the packets individually. Instead, it explores their level of heterogeneity in real time, using entropy to emphasize such feature. The results of the performance evaluation show that the proposed method is able to identify VoIP sessions accurately and simultaneously recognize the used speech codec.

A Quick Perspective on the Current State in Cybersecurity

Nowadays, cybersecurity makes headlines across the media and in companies, blogs, social networks, among other places. The Internet is a wild cyberspace, an arena for commercialization, consumerism, business, and leisure, to name a few activities. Networks, populations, and nations around the world, now interconnected through the Internet, rely on it for their daily lives. But some Internet users have learned to take advantage of vulnerable systems and of Internet technologies for their own good, sending out spam, phishing, data breaches, botnets, and other threats. An underground criminal network has emerged, creating complex malware kits for several purposes. “Hacktivism” has become a popular term with many supporters worldwide, but cyberwarfare is now on the rise, gaining more and more attention from nation-states. This chapter provides a quick overview of these topics, discussing them in a timely manner, referencing key events from the past while focusing on the present day.

Exploring Behavioral Patterns Through Entropy in Multimedia Peer-to-Peer Traffic

The inclusion of encryption or evasive techniques in popular applications increased the importance of characterizing network traffic based on behavior. This study aims to characterize peer-to-peer (P2P) traffic from the perspective of host computers by focusing on the packet lengths. The article explores the dissimilarities between the lengths of Internet Protocol (IP) packets generated by P2P and non-P2P applications. The heterogeneity of those lengths was assessed using entropy and compared for different classes of applications, through the implementation of a sliding analysis window. Initial observations show that the lengths of the packets generated by P2P applications are more varied than those of non-P2P applications. These patterns were used to implement a method to identify hosts running P2P applications. Unlike previous studies on this area, we used the heterogeneity of the packet lengths instead of the length value per se, and a sliding window calculation procedure was adopted to allow real-time processing. The results of this study can be used for the characterization of traffic generated by P2P applications, as well as for traffic classification and management purposes.

The Nature of Peer-to-Peer Traffic

The massive adoption of Peer-to-Peer (P2P) applications brings new challenges for network management. The increase of the bandwidth usage, the shift of the Internet habits of home users and the easiness to share and provide contents is changing the traffic characteristics, and breaking strong assumptions in which network design is based. As a response to concerns from network administrators and Internet Service Providers, traffic management is now a requirement instead of an option, making the traffic classification functionality into an essential administration tool. However, the evasive nature of most P2P applications renders the classification of their traffic a difficult task to achieve even through Deep Packet Inspections of the data units, mostly due to the application of encryption and randomizationmechanisms. In order to meet the demand for new and accurate methods for traffic classification in the dark, it is necessary to study and fully understand the deep nature of P2P traffic. In this chapter, the characteristics of this type of traffic are discussed and explained, and recent studies about traffic characterisation are introduced and analysed from the perspective that may enable their application for traffic classification.

Challenges and trends in optical networking: A bottom-up approach

Future bandwidth-intensive services, which will have a wide impact on our daily lives, from entertainment, to business and health-care, demand high capacity, flexible, resilient and secure underlying networks. Simultaneously, rising energy costs and climate change concerns are increasing the pressure to adopt power-efficient solutions in communication networks. Most of these requirements are best fulfilled with optical networks, which are expected to provide the targeted high capacities together with an increasing number of functionalities, leaving behind the label of ldquodumb piperdquo associated to them in early deployments. This paper presents an overview of the challenges and some of the trends in optical networking, covering developments in multiple layers of the protocol stack, from the physical up to the application layer, and aimed at different network segments, from the access to the core network.