4,229 research outputs found
Assessing and augmenting SCADA cyber security: a survey of techniques
SCADA systems monitor and control critical infrastructures of national importance such as power generation and distribution, water supply, transportation networks, and manufacturing facilities. The pervasiveness, miniaturisations and declining costs of internet connectivity have transformed these systems from strictly isolated to highly interconnected networks. The connectivity provides immense benefits such as reliability, scalability and remote connectivity, but at the same time exposes an otherwise isolated and secure system, to global cyber security threats. This inevitable transformation to highly connected systems thus necessitates effective security safeguards to be in place as any compromise or downtime of SCADA systems can have severe economic, safety and security ramifications. One way to ensure vital asset protection is to adopt a viewpoint similar to an attacker to determine weaknesses and loopholes in defences. Such mind sets help to identify and fix potential breaches before their exploitation. This paper surveys tools and techniques to uncover SCADA system vulnerabilities. A comprehensive review of the selected approaches is provided along with their applicability
Side-channel timing attack on content privacy of named data networking
Tese de Doutoramento em Engenharia Electrónica e de ComputadoresA diversity of current applications, such as Netflix, YouTube, and social media, have used the Internet mainly
as a content distribution network. Named Data Networking (NDN) is a network paradigm that attempts to
answer today’s applications need by naming the content. NDN promises an optimized content distribution
through a named content-centric design. One of the NDN key features is the use of in-network caching
to improve network efficiency in terms of content distribution. However, the cached contents may put the
consumer privacy at risk. Since the time response of cached contents is different from un-cached contents,
the adversary may distinguish the cached contents (targets) from un-cached ones, through the side-channel
timing responses. The scope of attack can be towards the content, the name, or the signature. For instance,
the adversary may obtain the call history, the callee or caller location on a trusted Voice over NDN (VoNDN)
and the popularity of contents in streaming applications (e.g. NDNtube, NDNlive) through side-channel
timing responses of the cache.
The side-channel timing attack can be mitigated by manipulating the time of the router responses. The
countermeasures proposed by other researches, such as additional delay, random/probabilistic caching,
group signatures, and no-caching can effectively be used to mitigate the attack. However, the content
distribution may be affected by pre-configured countermeasures which may go against the goal of the
original NDN paradigm. In this work, the detection and defense (DaD) approach is proposed to mitigate the
attack efficiently and effectively. With the DaD usage, an attack can be detected by a multi-level detection
mechanism, in order to apply the countermeasures against the adversarial faces. Also, the detections can
be used to determine the severity of the attack. In order to detect the behavior of an adversary, a brute-force
timing attack was implemented and simulated with the following applications and testbeds: i. a trusted
application that mimics the VoNDN and identifies the cached certificate on a worldwide NDN testbed, and
ii. a streaming-like NDNtube application to identify the popularity of videos on the NDN testbed and AT&T
company. In simulation primary results showed that the multi-level detection based on DaD mitigated the
attack about 39.1% in best-route, and 36.6% in multicast communications. Additionally, the results showed
that DaD preserves privacy without compromising the efficiency benefits of in-network caching in NDNtube
and VoNDN applications.Várias aplicações atuais, como o Netflix e o YouTube, têm vindo a usar a Internet como uma rede de
distribuição de conteúdos. O Named Data Networking (NDN) é um paradigma recente nas redes de comunicações
que tenta responder às necessidades das aplicações modernas, através da nomeação dos
conteúdos. O NDN promete uma otimização da distribuição dos conteúdos usando uma rede centrada
nos conteúdos. Uma das características principais do NDN é o uso da cache disponivel nos nós da rede
para melhorar a eficiência desta em termos de distribuição de conteúdos. No entanto, a colocação dos
conteúdos em cache pode colocar em risco a privacidade dos consumidores. Uma vez que a resposta
temporal de um conteúdo em cache é diferente do de um conteúdo que não está em cache, o adversário
pode distinguir os conteúdos que estão em cache dos que não estão em cache, através das respostas de
side-channel. O objectivo do ataque pode ser direcionado para o conteúdo, o nome ou a assinatura da
mensagem. Por exemplo, o adversário pode obter o histórico de chamadas, a localização do callee ou do
caller num serviço seguro de voz sobre NDN (VoNDN) e a popularidade do conteúdos em aplicações de
streaming (e.g. NDNtube, NDNlive) através das respostas temporais de side-channel.
O side-channel timing attack pode ser mitigado manipulando o tempo das respostas dos routers. As
contramedidas propostas por outros pesquisadores, tais como o atraso adicional, o cache aleatório /probabilístico,
as assinaturas de grupo e não fazer cache, podem ser efetivamente usadas para mitigar um
ataque. No entanto, a distribuição de conteúdos pode ser afetada por contramedidas pré-configuradas
que podem ir contra o propósito original do paradigma NDN. Neste trabalho, a abordagem de detecção e
defesa (DaD) é proposta para mitigar o ataque de forma eficiente e eficaz. Com o uso do DaD, um ataque
pode ser detectado por um mecanismo de detecção multi-nível, a fim de aplicar as contramedidas contra
as interfaces dos adversários. Além disso, as detecções podem ser usadas para determinar a gravidade
do ataque. A fim de detectar o comportamento de um adversário, um timing attack de força-bruta foi
implementado e simulado com as seguintes aplicações e plataformas (testbeds): i. uma aplicação segura
que implementa o VoNDN e identifica o certificado em cache numa plataforma NDN mundial; e ii. uma
aplicação de streaming do tipo NDNtube para identificar a popularidade de vídeos na plataforma NDN da
empresa AT&T. Os resultados da simulação mostraram que a detecção multi-nível oferecida pelo DaD atenuou
o ataque cerca de 39,1% em best-route e 36,5% em comunicações multicast. Para avaliar o efeito nos
pedidos legítimos, comparou-se o DaD com uma contramedida estática, tendo-se verificado que o DaD foi
capaz de preservar todos os pedidos legítimos
RAPTOR: Routing Attacks on Privacy in Tor
The Tor network is a widely used system for anonymous communication. However,
Tor is known to be vulnerable to attackers who can observe traffic at both ends
of the communication path. In this paper, we show that prior attacks are just
the tip of the iceberg. We present a suite of new attacks, called Raptor, that
can be launched by Autonomous Systems (ASes) to compromise user anonymity.
First, AS-level adversaries can exploit the asymmetric nature of Internet
routing to increase the chance of observing at least one direction of user
traffic at both ends of the communication. Second, AS-level adversaries can
exploit natural churn in Internet routing to lie on the BGP paths for more
users over time. Third, strategic adversaries can manipulate Internet routing
via BGP hijacks (to discover the users using specific Tor guard nodes) and
interceptions (to perform traffic analysis). We demonstrate the feasibility of
Raptor attacks by analyzing historical BGP data and Traceroute data as well as
performing real-world attacks on the live Tor network, while ensuring that we
do not harm real users. In addition, we outline the design of two monitoring
frameworks to counter these attacks: BGP monitoring to detect control-plane
attacks, and Traceroute monitoring to detect data-plane anomalies. Overall, our
work motivates the design of anonymity systems that are aware of the dynamics
of Internet routing
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