This paper describes a technique for tracing anonymous packet flooding attacks in the Internet back towards their source. This work is motivated by the increased frequency and sophistication of denial-of-service attacks and by the difficulty in tracing packets with incorrect, or “spoofed”, source addresses. In this paper we describe a general purpose traceback mechanism based on probabilistic packet marking in the network. Our approach allows a victim to identify the network path(s) traversed by attack traffic without requiring interactive operational support from Internet Service Providers (ISPs). Moreover, this traceback can be performed “post-mortem ” – after an attack has completed. We present an implementation of this technology that is incrementally deployable, (mostly) backwards compatible and can be efficiently implemented using conventional technology. 1.

In this paper, we seek to answer a simple question: "How prevalent are denial-of-service attacks in the Internet today?". Our motivation is to understand quantitatively the nature of the current threat as well as to enable longerterm analyses of trends and recurring patterns of attacks. We present a new technique, called "backscatter analysis", that provides an estimate of worldwide denial-of-service activity. We use this approach on three week-long datasets to assess the number, duration and focus of attacks, and to characterize their behavior. During this period, we observe more than 12,000 attacks against more than 5,000 distinct targets, ranging from well known ecommerce companies such as Amazon and Hotmail to small foreign ISPs and dial-up connections. We believe that our work is the only publically available data quantifying denial-of-service activity in the Internet.

Defending against distributed denial-of-service attacks is one of the hardest security problems on the Internet today. One difficulty to thwart these attacks is to trace the sourec of the attacks because they often use incorrect, or spoofed IP source addresses to disguide the true origin. In this paper, we present two new schemes, the Advanced Marking Scheme and the Authenticated Marking Scheme, which allow the victim to traceback the approcimate origin of the spoofed Ip packets. Our techniques feature low network and router overhead, and support incremental deployment. In contrast to previous work, our techniques have significantly higher precision (lower false positive rate) and lower computation overhead for the victim to reconstruct the attack paths under large scale distributed denial-of-service attacks. Furthermore the Authenticaed Marking Scheme provides efficient authentication of routers' markings such that even a compromised router cannot forge or tamper markings from other uncompromised routers.

Abstract. This paper develops the concept of victim-assistance for denial of service (DoS) mitigation. The proposed concept is utilized within a simple, yet effective scheme designed for mitigating TCP-based reflector DoS attacks. The proposed scheme, called SYN number based filtering (SNF), takes into account the TCP’s connection establishment behavior and the inherent features of the attack itself. The main idea of the SNF scheme is to restrict the choice of the initial sequence numbers of SYN packets to certain pattern, such that corresponding SYN-ACK packets can be validated at the ISP’s perimeter. We evaluate the proposed scheme through analytical studies for classical and advanced attacks using two performance metrics, namely, the false positive and false negative rates. Our analysis shows that the proposed scheme offers low false positive and false negative rates. In addition, we identify several research problems based on the proposed concept. 1

In this paper, we seek to answer a simple question: "How prevalent are denial-of-service attacks in the Internet today ?". Our motivation is to understand quantitatively the nature of the current threat as well as to enable longerterm analyses of trends and recurring patterns of attacks. We present a new technique, called "backscatter analysis ", that provides an estimate of worldwide denial-ofservice activity. We use this approach on three week-long datasets to assess the number, duration and focus of attacks, and to characterize their behavior. During this period, we observe more than 12,000 attacks against more than 5,000 distinct targets, ranging from well known ecommerce companies such as Amazon and Hotmail to small foreign ISPs and dial-up connections. We believe that our work is the only publically available data quantifying denial-of-service activity in the Internet.

this paper: q DDoS Attack Infrastructure: Hackers form their own community and they share resources among themselves. When one Internet host is compromised (a resource for the hackers), the host identity and the key to access this host is announced to all the hackers. Gradually, compromised hosts are organized and connected together as a DDoS attack infrastructure. In this infrastructure, some hosts play the role of masters, while others are slaves