Formal Model of Time for Analyzing Denial-of-Service Attacks

A denial-of-service attack (DoS attack) is an attempt to make a system resource unavailable to its intended users. Several types of DoS attacks are known. A SYN flood attack is a typical DoS attack, exploiting the vulnerability of TCP’s three-way handshake with respect to imbalances between the computational costs of clients and server. In addition to cost imbalance, the amount of cost over a given short term is also an indispensable factor in DoS attacks, including SYN flood attacks. In this paper, we propose a process calculus for formalizing computational costs and cost amounts over the short term. This procedure is called the“timed spice-calculus,”and was developed by improving the prototypic theory of preliminary studies, known as the spice-calculus. Time is modeled as a hierarchical ordered structure with respect to types of processing.