Defending Against Denial of Service

Civil Society currently faces significant cyber threats. At the top of the list of those threats are Denial of Service (DoS) attacks. The websites of many organizations and individuals have already come under such attacks, and the frequency of those attacks are on the rise. Civil Society frequently does not have the kinds of resources or technical know-how that is available to commercial enterprise and government websites, and often have to exist in adverse political environments where every avenue available, both legal and illegal, is used against them. Therefore, the threat of DoS attacks is unlikely to go away any time soon.A Denial of Service (DoS) attack is any attack that overwhelms a website, causing the content normally provided by that website to no longer be available to regular visitors of the website. Distributed Denial of Service (DDoS) attacks are traffic volumebased attacks originating from a large number of computers, which are usually compromised workstations. These workstations, known as 'zombies', form a widely distributed attack network called a 'botnet'. While many modern Denial of Service attacks are Distributed Denial of Service attacks, this is certainly not true for all denials of service experienced by websites. Therefore, when users first start experiencing difficulty in getting to the website content, it should not be assumed that the site is under a DDoS attack. Many forms of DoS are far easier to implement than DDoS, and so these attacks are still used by parties with malicious intent. Many such DoS attacks are easier to defend against once the mechanism used to cause the denial of service is known. Therefore, it is paramount to do proper analysis of attack traffic when a site becomes unable to perform its normal function. There are two parts to this guide. The first part outlines preparatory steps that can be taken by Civil Society organizations to improve their website's resilience, should it come under attack. However, we do understand that most Civil Society organizations' first introduction to DoS attacks comes when they suddenly find themselves the victim of an attack. The second part of this guide provides a step-by-step process to assist the staff of NGOs to efficiently deal with that stressful situation

Business and social evaluation of denial of service attacks in view of scaling economic counter-measures

This paper gives an analytical method to determine the economic and indirect implications of denial of service and distributed denial of service attacks. It is based on time preference dynamics applied to the monetary mass for the restoration of capabilities, on long term investments to rebuild capabilities, and of the usability level of the capabilities after an attack. A simple illustrative example is provided for a denial of service on a corporate data centre. The needed data collection methodologies are categorized by classes of targets. The use of the method is explained in the context of legal or policy driven dissuasive, retaliation or compensation/ restoration actions. A concrete set of deployment cases in the communications service and transport industries is discussed. The conclusion includes policy recommendations as well as information exchange requirements.Cyberwar; Denial of service; Business implications; Social implications; Mobile communications; Insurance

Towards Stabilization of Distributed Systems under Denial-of-Service

In this paper, we consider networked distributed systems in the presence of Denial-of-Service (DoS) attacks, namely attacks that prevent transmissions over the communication network. First, we consider a simple and typical scenario where communication sequence is purely Round-robin and we explicitly calculate a bound of attack frequency and duration, under which the interconnected large-scale system is asymptotically stable. Second, trading-off system resilience and communication load, we design a hybrid transmission strategy consisting of Zeno-free distributed event-triggered control and Round-robin. We show that with lower communication loads, the hybrid communication strategy enables the systems to have the same resilience as in pure Round-robin

Distributed Denial-of-Service Defense System

Distributed denial-of-service (DoS) attacks present a great threat to the Internet, and existing security mechanisms cannot detect or stop them successfully. The problem lies in the distributed nature of attacks, which engages the power of a vast number of coordinated hosts. To mitigate the impacts of DDoS attacks, it is important to develop such defenses system that canbothdetect andreact against ongoing attacks. The attacks ideally should be stopped as close to the sources as possible, saving network resources andreducing congestion. The DDoS defense system that is deployed at the source-end should prevent the machines at associated network from participating in DDoS attacks. The primary objective of this project, which is developing a DDoS defense system, is to provide good service to a victim's legitimate clients during the attack, thus canceling the denial-of-service effect. The scope of study will coverthe aspect of howthe attack detection algorithms work and identify the attack traffic, hence develop appropriate attack responses. As a source-end defense against DDoS attacks, the attack flows can be stopped before they enter the Internet core and before they aggregate with other attack flows. The methodology chosen for this project is the combination of sequential and iterative approaches of the software development process, which comprises of six main phases, which are initial planning phase, requirement definition phase, system design phase, coding and testing phase, implementation phase, and lastly maintenance and support phase. The system used a source router approach, in which the source router serves as a gateway between the source network containing some of the attack nodes and the rest of the Internet, to detectand limitDDoS streams long before they reach the target. This will be covered in the Findings section of the report. TheDiscussion section will be focus more onthe architecture onthe system, which having three important component; observation, rate-limiting and traffic-policing