International Journal of Computer Applications
Countering Distributed Denial of Service (DDoS) attacks is becoming ever more challenging with the vast resources and techniques increasingly available to attackers. Derived from the low layers, new application-layer-based DDoS attacks utilizing legitimate HTTP requests to overwhelm victim resources are more undetectable. The case may be more serious when such attacks mimic or occur during the flash crowd event of a popular website. The problem concerned in this paper is sophisticated attacks that are protocol compliant, non-intrusive, and utilize legitimate application-layer requests to overwhelm system resources. It characterizes application-layer resource attacks as either request flooding, asymmetric, or repeated one-shot, on the basis of the application workload parameters that they exploit.