DDoS DDoS is distributed denial of service, or an attack that focuses on using the power of a large number of computers to deny users access to a particular service. This attack is powerful and can often bring down entire websites by hitting them with a large amount of traffic. It is difficult to defend against when the attacker is using a botnet because the machines are distributed across the ...

Distributed denial-of-service (DDOS) flood attacks remain a big issue in network security. Real events of DDOS flood attacks show that an attacked site (e.g., server) usually may not be overwhelmed immediately at the moment attack packets arrive at that site but sometime late. Therefore, a site has a performance to resist DDOS flood attacks. To test such a performance, data synthesizer is desir...

Cloud Computing is a computing model that allows ubiquitous, convenient and on-demand access to a shared pool of highly configurable resources (e.g., networks, servers, storage, applications and services). Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) attacks are serious threats to the Cloud services’ availability due to numerous new vulnerabilities introduced by the nature o...

Denial of Service (DoS) or Distributed Denial of Service (DDoS) is a powerful attack which prevents the system from providing services to its legitimate users. Several approaches exist to filter network-level attacks, but application-level attacks are harder to detect at the firewall. Filtering at application level can be computationally expensive and difficult to scale, while still creating bo...

Tor is a distributed onion-routing network used for achieving anonymity and resisting censorship online. Because of Tor’s growing popularity, it is attracting increasingly larger threats against which it was not securely designed. In this paper, we present the Sniper Attack, an extremely low cost but highly destructive denial of service attack against Tor that an adversary may use to anonymousl...

Computer criminals regularly construct large distributed attack networks comprised of many thousands of compromised computers around the globe. Once constituted, these attack networks are used to perform computer crimes, creating yet other sets of victims of secondary computer crimes, such as denial of service attacks, spam delivery, theft of personal and financial information for performing fr...

In this paper we discuss techniques to prevent Distributed Denial of Service (DDoS) attacks within the ISP domain and extend the scheme to prevent the attack in multiple ISP domains. With a new packet marking technique and agent design, our model is able to identify the approximate source of attack with a single packet and has many features to minimise DDoS attacks.