272 research outputs found
ADVANCED RANDOM TIME QUEUE BLOCKING WITH TRAFFIC PREDICTION FOR DEFENSE OF LOW-RATE DOS ATTACKS AGAINST APPLICATION SERVERS
Among many strategies of Denial of Services, low-rate traffic denial-of-service (DoS) attacks are more significant. This strategy denies the services of a network by detection of the vulnerabilities in performance of the application. In this research, an efficient defence methodology is developed against low-rate DoS attack in the application servers. Though, the Improved Random Time Queue Blocking (IRTQB) technique can eliminate the vulnerabilities in the network and also avoiding the attacker from capturing all the server queue positions by defining a spatial similarity metric (SSM). However, the differentiation of the attack requests from the legitimate users’ is not always efficient since only the source IP addresses and the record timestamp are considered in the SSM. It was improved by using Advanced Random Time Queue Blocking (ARTQB) scheme that employed Bandwidth utilization of attacker in IRTQB to detect the DoS attack that normally consumes a huge number of resources of the server. However, this method becomes ineffective when the attack consumes more network traffic. In this paper, an efficient detection technique called Advanced Random Time Queue Blocking with Traffic Prediction (ARTQB-TP) is proposed for defining SSM which contains, Source IP, timestamp, Bandwidth between two requests and the difference between the attack traffic and legitimate traffic. The ARTQB-TP technique is utilized to reduce the attack efficiency in 18 different server configurations which are more vulnerable to the DoS attacks and where the attacks may also have a chance to improve its effectiveness. Experimental results show that the proposed system performs better protection of application servers against the LRDoS attacks by solving its impacts on any kind of server architectures and reduced the attack efficiencies of all the types of attack strategies
Analysis of the SYN Flood DoS Attack
The paper analyzes systems vulnerability targeted by TCP (Transmission Control Protocol) segments when SYN flag is ON, which gives space for a DoS (Denial of Service) attack called SYN flooding attack or more often referred as a SYN flood attack. The effects of this type of attack are analyzed and presented in OPNET simulation environment. Furthermore, the paper presents two anomaly detection algorithms as an effective mechanism against this type of attack. Finally, practical approaches against SYN flood attack for Linux and Windows environment are shown
A Defense Framework Against Denial-of-Service in Computer Networks
Denial-of-Service (DoS) is a computer security problem that poses a serious challenge totrustworthiness of services deployed over computer networks. The aim of DoS attacks isto make services unavailable to legitimate users, and current network architectures alloweasy-to-launch, hard-to-stop DoS attacks. Particularly challenging are the service-level DoSattacks, whereby the victim service is flooded with legitimate-like requests, and the jammingattack, in which wireless communication is blocked by malicious radio interference. Theseattacks are overwhelming even for massively-resourced services, and effective and efficientdefenses are highly needed. This work contributes a novel defense framework, which I call dodging, against service-level DoS and wireless jamming. Dodging has two components: (1) the careful assignment ofservers to clients to achieve accurate and quick identification of service-level DoS attackersand (2) the continuous and unpredictable-to-attackers reconfiguration of the client-serverassignment and the radio-channel mapping to withstand service-level and jamming DoSattacks. Dodging creates hard-to-evade baits, or traps, and dilutes the attack "fire power".The traps identify the attackers when they violate the mapping function and even when theyattack while correctly following the mapping function. Moreover, dodging keeps attackers"in the dark", trying to follow the unpredictably changing mapping. They may hit a fewtimes but lose "precious" time before they are identified and stopped. Three dodging-based DoS defense algorithms are developed in this work. They are moreresource-efficient than state-of-the-art DoS detection and mitigation techniques. Honeybees combines channel hopping and error-correcting codes to achieve bandwidth-efficientand energy-efficient mitigation of jamming in multi-radio networks. In roaming honeypots, dodging enables the camouflaging of honeypots, or trap machines, as real servers,making it hard for attackers to locate and avoid the traps. Furthermore, shuffling requestsover servers opens up windows of opportunity, during which legitimate requests are serviced.Live baiting, efficiently identifies service-level DoS attackers by employing results fromthe group-testing theory, discovering defective members in a population using the minimumnumber of tests. The cost and benefit of the dodging algorithms are analyzed theoretically,in simulation, and using prototype experiments
A Game Theoretic approach based virtual machine migration for cloud environment security
In cloud computing environment, static configurations can provide for the attackers an environment too easy for exploitation and discovering the network vulnerabilities in order to compromise the network and launching intrusions; while dynamic reconfiguration seeks to develop a virtual machine (VM) migration over the cloud by applying unpredictability of network configuration’s change, and thus improving the system security. In this work a novel approach that performs proactive and reactive measures to ensure a high availability and to minimize the attack surface using VM migration is proposed. This interaction between attack and defense systems was formulated as game model. As result, we have calculated the Nash equilibrium and the utilities for the both attacker and defender, evaluate the parameters which can maximize the defender’s utility when the VM migration was planned and identify the potential attack paths. Therefore, the effectiveness of the game model was validated by some numerical results that determine optimal migration strategies in order to ensure the security of the system
Misbehaving TCP Receivers Can Cause Internet-Wide Congestion Collapse
An "optimistic" acknowledgment (OptAck) is an acknowledgment
sent by a misbehaving client for a data segment that it has not
received. Whereas previous work has focused on OptAck as a means to
greedily improve end-to-end performance, we study OptAck exclusively
as a denial of service attack. Specifically, an attacker sends
optimistic acknowledgments to many victims in parallel, thereby
amplifying its effective bandwidth by a factor of 30 million (worst
case). Thus, even a relatively modest attacker can totally saturate
the paths from many victims back to the attacker. Worse, a
distributed network of compromised machines (``zombies'') can exploit
this attack in parallel to bring about wide-spread, sustained
congestion collapse.
We implement this attack both in simulation and in a wide-area
network, and show it severity both in terms of number of packets and
total traffic generated. We engineer and implement a novel solution
that does not require client or network modifications allowing for
practical deployment. Additionally, we demonstrate the solution's
efficiency on a real network
Towards Protection Against Low-Rate Distributed Denial of Service Attacks in Platform-as-a-Service Cloud Services
Nowadays, the variety of technology to perform daily tasks is abundant and different business
and people benefit from this diversity. The more technology evolves, more useful it gets and in
contrast, they also become target for malicious users. Cloud Computing is one of the technologies
that is being adopted by different companies worldwide throughout the years. Its popularity
is essentially due to its characteristics and the way it delivers its services. This Cloud expansion
also means that malicious users may try to exploit it, as the research studies presented throughout
this work revealed. According to these studies, Denial of Service attack is a type of threat
that is always trying to take advantage of Cloud Computing Services.
Several companies moved or are moving their services to hosted environments provided by Cloud
Service Providers and are using several applications based on those services. The literature on
the subject, bring to attention that because of this Cloud adoption expansion, the use of applications
increased. Therefore, DoS threats are aiming the Application Layer more and additionally,
advanced variations are being used such as Low-Rate Distributed Denial of Service attacks.
Some researches are being conducted specifically for the detection and mitigation of this kind
of threat and the significant problem found within this DDoS variant, is the difficulty to differentiate
malicious traffic from legitimate user traffic. The main goal of this attack is to exploit
the communication aspect of the HTTP protocol, sending legitimate traffic with small changes
to fill the requests of a server slowly, resulting in almost stopping the access of real users to
the server resources during the attack.
This kind of attack usually has a small time window duration but in order to be more efficient,
it is used within infected computers creating a network of attackers, transforming into
a Distributed attack. For this work, the idea to battle Low-Rate Distributed Denial of Service
attacks, is to integrate different technologies inside an Hybrid Application where the main goal
is to identify and separate malicious traffic from legitimate traffic. First, a study is done to
observe the behavior of each type of Low-Rate attack in order to gather specific information
related to their characteristics when the attack is executing in real-time. Then, using the Tshark
filters, the collection of those packet information is done. The next step is to develop combinations
of specific information obtained from the packet filtering and compare them. Finally,
each packet is analyzed based on these combinations patterns. A log file is created to store the
data gathered after the Entropy calculation in a friendly format.
In order to test the efficiency of the application, a Cloud virtual infrastructure was built using
OpenNebula Sandbox and Apache Web Server. Two tests were done against the infrastructure,
the first test had the objective to verify the effectiveness of the tool proportionally against the
Cloud environment created. Based on the results of this test, a second test was proposed to
demonstrate how the Hybrid Application works against the attacks performed. The conclusion
of the tests presented how the types of Slow-Rate DDoS can be disruptive and also exhibited
promising results of the Hybrid Application performance against Low-Rate Distributed Denial of
Service attacks. The Hybrid Application was successful in identify each type of Low-Rate DDoS,
separate the traffic and generate few false positives in the process. The results are displayed
in the form of parameters and graphs.Actualmente, a variedade de tecnologias que realizam tarefas diárias é abundante e diferentes
empresas e pessoas se beneficiam desta diversidade. Quanto mais a tecnologia evolui, mais
usual se torna, em contraposição, essas empresas acabam por se tornar alvo de actividades maliciosas.
Computação na Nuvem é uma das tecnologias que vem sendo adoptada por empresas
de diferentes segmentos ao redor do mundo durante anos. Sua popularidade se deve principalmente
devido as suas características e a maneira com o qual entrega seus serviços ao cliente.
Esta expansão da Computação na Nuvem também implica que usuários maliciosos podem tentar
explorá-la, como revela estudos de pesquisas apresentados ao longo deste trabalho. De acordo
também com estes estudos, Ataques de Negação de Serviço são um tipo de ameaça que sempre
estão a tentar tirar vantagens dos serviços de Computação na Nuvem.
Várias empresas moveram ou estão a mover seus serviços para ambientes hospedados fornecidos
por provedores de Computação na Nuvem e estão a utilizar várias aplicações baseadas nestes
serviços. A literatura existente sobre este tema chama atenção sobre o fato de que, por conta
desta expansão na adopção à serviços na Nuvem, o uso de aplicações aumentou. Portanto,
ameaças de Negação de Serviço estão visando mais a camada de aplicação e também, variações
de ataques mais avançados estão sendo utilizadas como Negação de Serviço Distribuída de Baixa
Taxa. Algumas pesquisas estão a ser feitas relacionadas especificamente para a detecção e mitigação
deste tipo de ameaça e o maior problema encontrado nesta variante é diferenciar tráfego
malicioso de tráfego legítimo. O objectivo principal desta ameaça é explorar a maneira como o
protocolo HTTP trabalha, enviando tráfego legítimo com pequenas modificações para preencher
as solicitações feitas a um servidor lentamente, tornando quase impossível para usuários legítimos
aceder os recursos do servidor durante o ataque.
Este tipo de ataque geralmente tem uma janela de tempo curta mas para obter melhor eficiência,
o ataque é propagado utilizando computadores infectados, criando uma rede de ataque,
transformando-se em um ataque distribuído. Para este trabalho, a ideia para combater Ataques
de Negação de Serviço Distribuída de Baixa Taxa é integrar diferentes tecnologias dentro de uma
Aplicação Híbrida com o objectivo principal de identificar e separar tráfego malicioso de tráfego
legítimo. Primeiro, um estudo é feito para observar o comportamento de cada tipo de Ataque
de Baixa Taxa, a fim de recolher informações específicas relacionadas às suas características
quando o ataque é executado em tempo-real. Então, usando os filtros do programa Tshark, a
obtenção destas informações é feita. O próximo passo é criar combinações das informações específicas
obtidas dos pacotes e compará-las. Então finalmente, cada pacote é analisado baseado
nos padrões de combinações feitos. Um arquivo de registo é criado ao fim para armazenar os
dados recolhidos após o cálculo da Entropia em um formato amigável.
A fim de testar a eficiência da Aplicação Híbrida, uma infra-estrutura Cloud virtual foi construída
usando OpenNebula Sandbox e servidores Apache. Dois testes foram feitos contra a
infra-estrutura, o primeiro teste teve o objectivo de verificar a efectividade da ferramenta
proporcionalmente contra o ambiente de Nuvem criado. Baseado nos resultados deste teste,
um segundo teste foi proposto para verificar o funcionamento da Aplicação Híbrida contra os
ataques realizados. A conclusão dos testes mostrou como os tipos de Ataques de Negação de
Serviço Distribuída de Baixa Taxa podem ser disruptivos e também revelou resultados promissores relacionados ao desempenho da Aplicação Híbrida contra esta ameaça. A Aplicação Híbrida
obteve sucesso ao identificar cada tipo de Ataque de Negação de Serviço Distribuída de Baixa
Taxa, em separar o tráfego e gerou poucos falsos positivos durante o processo. Os resultados
são exibidos em forma de parâmetros e grafos
Evaluation of Windows Servers Security Under ICMP and TCP Denial of Service Attacks
Securing server from Distributed denial of service (DDoS) attacks is a challenging task for network operators. DDOS attacks are known to reduce the performance of web based applications and reduce the number of legitimate client connections. In this thesis, we evaluate performance of a Windows server 2003 under these attacks. In this thesis, we also evaluate and compare effectiveness of three different protection mechanisms, namely SYN Cache, SYN Cookie and SYN proxy protection methods, to protect against TCP SYN DDoS attacks. It is found that the SYN attack protection at the server is more effective at lower loads of SYN attack traffic, whereas the SYN cookies protection is more effective at higher loads compared to other methods
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