Analysis of DoS attack methods on IMS system

Users of IP Multimedia Subsystem (IMS) usually access the system from IMS provider´s own fixed or mobile IP access network but providers also allow their users to access the IMS system from the Internet. With connection to the Internet the IMS system is exposed to denial of services (DoS) attacks that represent a real security threat to the IMS systems. DoS attacks could be carried out with various types of packets that produce different impact on targeted IMS system. This paper analyzes DoS attack methods on an IMS system, their impact on different parts of the IMS system and suggests a protection method for reduction of impact of IP spoofing DoS attacks on the IMS system.