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

Packet filter performance monitor (anti-DDOS algorithm for hybrid topologies)

DDoS attacks are increasingly becoming a major problem. According to Arbor Networks, the largest DDoS attack reported by a respondent in 2015 was 500 Gbps. Hacker News stated that the largest DDoS attack as of March 2016 was over 600 Gbps, and the attack targeted the entire BBC website. With this increasing frequency and threat, and the average DDoS attack duration at about 16 hours, we know for certain that DDoS attacks will not be going away anytime soon. Commercial companies are not effectively providing mitigation techniques against these attacks, considering that major corporations face the same challenges. Current security appliances are not strong enough to handle the overwhelming traffic that accompanies current DDoS attacks. There is also a limited research on solutions to mitigate DDoS attacks. Therefore, there is a need for a means of mitigating DDoS attacks in order to minimize downtime. One possible solution is for organizations to implement their own architectures that are meant to mitigate DDoS attacks. In this dissertation, we present and implement an architecture that utilizes an activity monitor to change the states of firewalls based on their performance in a hybrid network. Both firewalls are connected inline. The monitor is mirrored to monitor the firewall states. The monitor reroutes traffic when one of the firewalls become overwhelmed due to a HTTP DDoS flooding attack. The monitor connects to the API of both firewalls. The communication between the rewalls and monitor is encrypted using AES, based on PyCrypto Python implementation. This dissertation is structured in three parts. The first found the weakness of the hardware firewall and determined its threshold based on spike and endurance tests. This was achieved by flooding the hardware firewall with HTTP packets until the firewall became overwhelmed and unresponsive. The second part implements the same test as the first, but targeted towards the virtual firewall. The same parameters, test factors, and determinants were used; however a different load tester was utilized. The final part was the implementation and design of the firewall performance monitor. The main goal of the dissertation is to minimize downtime when network firewalls are overwhelmed as a result of a DDoS attack

Mitigating Denial-of-Service Attacks on VoIP Environment

IP telephony refers to the use of Internet protocols to provide voice, video, and data in one integrated service over LANs, BNs, MANs, not WANs. VoIP provides three key benefits compared to traditional voice telephone services. First, it minimizes the need fro extra wiring in new buildings. Second, it provides easy movement of telephones and the ability of phone numbers to move with the individual. Finally, VoIP is generally cheaper to operate because it requires less network capacity to transmit the same voice telephone call over an increasingly digital telephone network (FitzGerald & Dennis, 2007 p. 519). Unfortunately, benefits of new electronic communications come with proportionate risks. Companies experience losses resulting from attacks on data networks. There are direct losses like economic theft, theft of trade secrets and digital data, as well as indirect losses that include loss of sales, loss of competitive advantage etc. The companies need to develop their security policies to protect their businesses. But the practice of information security has become more complex than ever. The research paper will be about the major DoS threats the company’s VoIP environment can experience as well as best countermeasures that can be used to prevent them and make the VoIP environment and, therefore, company’s networking environment more secure

Denial-of-service attack modelling and detection for HTTP/2 services

Businesses and society alike have been heavily dependent on Internet-based services, albeit with experiences of constant and annoying disruptions caused by the adversary class. A malicious attack that can prevent establishment of Internet connections to web servers, initiated from legitimate client machines, is termed as a Denial of Service (DoS) attack; volume and intensity of which is rapidly growing thanks to the readily available attack tools and the ever-increasing network bandwidths. A majority of contemporary web servers are built on the HTTP/1.1 communication protocol. As a consequence, all literature found on DoS attack modelling and appertaining detection techniques, addresses only HTTP/1.x network traffic. This thesis presents a model of DoS attack traffic against servers employing the new communication protocol, namely HTTP/2. The HTTP/2 protocol significantly differs from its predecessor and introduces new messaging formats and data exchange mechanisms. This creates an urgent need to understand how malicious attacks including Denial of Service, can be launched against HTTP/2 services. Moreover, the ability of attackers to vary the network traffic models to stealthy affects web services, thereby requires extensive research and modelling. This research work not only provides a novel model for DoS attacks against HTTP/2 services, but also provides a model of stealthy variants of such attacks, that can disrupt routine web services. Specifically, HTTP/2 traffic patterns that consume computing resources of a server, such as CPU utilisation and memory consumption, were thoroughly explored and examined. The study presents four HTTP/2 attack models. The first being a flooding-based attack model, the second being a distributed model, the third and fourth are variant DoS attack models. The attack traffic analysis conducted in this study employed four machine learning techniques, namely Naïve Bayes, Decision Tree, JRip and Support Vector Machines. The HTTP/2 normal traffic model portrays online activities of human users. The model thus formulated was employed to also generate flash-crowd traffic, i.e. a large volume of normal traffic that incapacitates a web server, similar in fashion to a DoS attack, albeit with non-malicious intent. Flash-crowd traffic generated based on the defined model was used to populate the dataset of legitimate network traffic, to fuzz the machine learning-based attack detection process. The two variants of DoS attack traffic differed in terms of the traffic intensities and the inter-packet arrival delays introduced to better analyse the type and quality of DoS attacks that can be launched against HTTP/2 services. A detailed analysis of HTTP/2 features is also presented to rank relevant network traffic features for all four traffic models presented. These features were ranked based on legitimate as well as attack traffic observations conducted in this study. The study shows that machine learning-based analysis yields better classification performance, i.e. lower percentage of incorrectly classified instances, when the proposed HTTP/2 features are employed compared to when HTTP/1.1 features alone are used. The study shows how HTTP/2 DoS attack can be modelled, and how future work can extend the proposed model to create variant attack traffic models that can bypass intrusion-detection systems. Likewise, as the Internet traffic and the heterogeneity of Internet-connected devices are projected to increase significantly, legitimate traffic can yield varying traffic patterns, demanding further analysis. The significance of having current legitimate traffic datasets, together with the scope to extend the DoS attack models presented herewith, suggest that research in the DoS attack analysis and detection area will benefit from the work presented in this thesis

Experimental evaluation of select servers and firewalls under denial of service security attacks

Internet security requires newer prevention mechanisms to be implemented on web-servers and routers. Firewall/Intrusion Prevention mechanisms (IPS) can be deployed on host servers or routers as an added line of defense against Internet attacks. In this thesis, we evaluate performance of security mechanisms provided by these devices against Distributed Denial of Service (DDoS) attacks. The host based firewalls on Windows servers-2003 and 2008 were evaluated. In this thesis, we also evaluated Juniper Networks Netscreen-5GT firewall/IPS, and Cisco ASA-5510/IPS that are used in protecting web-servers against DDoS attacks. It was found that the host based firewalls and protection mechanisms on the windows servers were not capable of defending against the DDoS attacks. Our performance evaluation showed the computing resource of the servers to be completely exhausted under these attacks. The evaluation of firewalls and IPS under different loads of attack had varying performance in supporting the number of web connections

A survey of defense mechanisms against distributed denial of service (DDOS) flooding attacks

Distributed Denial of Service (DDoS) flooding attacks are one of the biggest concerns for security professionals. DDoS flooding attacks are typically explicit attempts to disrupt legitimate users' access to services. Attackers usually gain access to a large number of computers by exploiting their vulnerabilities to set up attack armies (i.e., Botnets). Once an attack army has been set up, an attacker can invoke a coordinated, large-scale attack against one or more targets. Developing a comprehensive defense mechanism against identified and anticipated DDoS flooding attacks is a desired goal of the intrusion detection and prevention research community. However, the development of such a mechanism requires a comprehensive understanding of the problem and the techniques that have been used thus far in preventing, detecting, and responding to various DDoS flooding attacks. In this paper, we explore the scope of the DDoS flooding attack problem and attempts to combat it. We categorize the DDoS flooding attacks and classify existing countermeasures based on where and when they prevent, detect, and respond to the DDoS flooding attacks. Moreover, we highlight the need for a comprehensive distributed and collaborative defense approach. Our primary intention for this work is to stimulate the research community into developing creative, effective, efficient, and comprehensive prevention, detection, and response mechanisms that address the DDoS flooding problem before, during and after an actual attack. © 1998-2012 IEEE