Denial of service (DoS) attacks play a significant role in contemporary cyberspace scenarios. A variety of different DoS attacks pollute networks by exploring various vulnerabilities. A group of DoS called application DoS attacks explore application vulnerabilities. This work presents a tool that detects and blocks an application DoS called Slowloris on wireless mesh networks (WMNs). Our tool, called SDToW, is designed to effectively use the structure of the WMNs to block the Slowloris attack. SDToW uses three different modules to detect and block the attack. Each module has its specific tasks and thus optimizes the overall detection and block efficiency. Our solution blocks the attacker on its first WMN hop, reducing the malicious traffic on the network and avoiding further attacks from the blocked user. The comparison results show that SDToW performs with 66.7% less processing consumption and 89.1% less memory consumption than Snort. Our solution does not limit the number of parallel connections per user. Hence, by avoiding this limitation, SDToW has a lower incidence of false positive errors than Snort.

Resumo-A diversidade dos ataques de negação de serviço criam a necessidade de avanços em ferramentas que possam reduzir os impactos relativosà inacessibilidade do serviço. Estas ferramentas em sua maioria objetivam prevenir ataques, através de medidas de contenção. O trabalho proposto,é a criação de um IPS denominado IREMAC, responsável por fazer a contenção de ataques com base nos endereços IP e MAC de máquinas situadas na rede interna. Os resultados demostram que a solução proposta apresenta desempenho satisfatório em relação ao tempo de resposta do servidor após um ataque e redução de falsos positivos que impedem comunicações legítimas.Palavras-Chave-IPS, Segurança de Redes, DoS. Abstract-The diversity of denial of service attacks create the need for advances in tools that can reduce impacts on the inaccessibility of service. These tools use techniques mostly focused on prevent attack through containment measures. The work proposed is the creation of an IPS called IREMAC, responsible for making the restriction of an attacker by IP and MAC addresses. That restriction is focuses on attacks that take place within the network. The results demonstrate that the proposed solution presents a gain in performance on server response delay after an attack and reduce false positives that prevent legitimate communications.

In this paper, we propose three mechanisms to reduce the broadcast storm problem in wireless mesh networks based on the Named-Data Network (NDN) architecture. The goal of our mechanisms is to reduce the number of content requests forwarded by nodes and consequently, increase the network efficiency. The first proposed mechanism, called Probabilistic Interest Forwarding (PIF), randomly forwards content requests. The second mechanism, called Retransmission-Counter-based Forwarding (ReCIF), decides to forward content requests based on the number of retransmissions by adding a counter to the header of requests. The third mechanism, called ReCIF+PIF, combines the features of PIF and ReCIF to suppress content requests. We compare the performance of our mechanisms with both the NDN default forwarding mechanism and the Listen First Broadcast Later (LFBL) mechanism. Our proposals outperform the default NDN forwarding mechanism by up to 21% regarding the data delivery rate in dense networks and provide a 25% lower delivery delay than the default NDN. Our mechanisms accomplish this performance by only reducing the number of content requests forwarded by nodes. One of our mechanisms, PIF, outperforms LFBL regarding the data delivery rate and delivery delay by up to 263% and 55%, respectively, for high network contention levels.

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This paper proposes three mechanisms in order to reduce the broadcast storm problem in information-centric wireless mesh networks. The first one defines a probability to forward interest packets. The second one limits the number of interest packets forwarded based on the number of previous forwarding actions of these packets. The third one is a hybrid approach that combines the forwarding criteria of the two previous mechanisms. The performance of a information-centric wireless mesh networks is evaluated with the three proposed mechanisms and also with the default forwarding mechanism. The performance of such network is also compared with the one provided by a wireless mesh network based on the TCP/IP stack running the OLSR protocol. Results show the proposed mechanisms provide a delivery rate four times higher than the one provided by OLSR. In addition, our proposals outperform the default forwarding mechanism by up to 19% in terms of data delivery rate in dense scenarios with high number of hops between source and destination.