Biblio

The new paradigm software-defined networking (SDN) supports network innovation and makes the control of network operations more agile. The flow table is the main component of SDN switch which contains a set of flow entries that define how new flows are processed. Low-rate distributed denial-of-service (LR-DDoS) attacks are difficult to detect and mitigate because they behave like legitimate users. There are many detection methods for LR DDoS attacks in the literature, but none of these methods detect single-packet LR DDoS attacks. In fact, LR DDoS attackers exploit vulnerabilities in the mechanism of congestion control in TCP to either periodically retransmit burst attack packets for a short time period or to continuously launch a single attack packet at a constant low rate. In this paper, the proposed scheme detects LR-DDoS by examining all incoming packets and filtering the single packets sent from different source IP addresses to the same destination at a constant low rate. Sending single packets at a constant low rate will increase the number of flows at the switch which can make it easily overflowed. After detecting the single attack packets, the proposed scheme prevents LR-DDoS at its early stage by deleting the flows created by these packets once they reach the threshold. According to the results of the experiment, the scheme achieves 99.47% accuracy in this scenario. In addition, the scheme has simple logic and simple calculation, which reduces the overhead of the SDN controller.