Ehlert, S.S.EhlertRebahi, Y.Y.RebahiMagedanz, T.T.Magedanz2022-03-042022-03-042009https://publica.fraunhofer.de/handle/publica/21955110.1504/IJSN.2009.027344Security threats to Voice-over IP (VoIP) or IP Multimedia Subsystem (IMS) networks are becoming a major concern as their popularity increases. New attacks are being developed that directly target the underlying SIP protocol. To detect such kinds of attacks we are presenting a specification-based Intrusion Detection System (IDS) to recognise deviation from its expected protocol behaviour. We will present an implementation and show with measurements that this method is capable of attack detection and mitigation for different kinds of attacks directed towards a SIP infrastructure, with a focus on Denial-of-Service (DoS) message flooding.enSIPsession initiation protocolVoIPvoice over IPflooding attackDOSdenial-of-serviceIDSintrusion detection systemstate machineattack mitigationsecurity threadIP multimedia subsystem004400journal article