SIP-based networks are becoming the de-facto standard for voice, video and instant messaging services. Being exposed to many threats while playing an essential role in the operation of essential services, the need for dedicated security management approaches is rapidely increasing. In this paper we present one dedicated security management approach based on a SIP specific vulnerability aware stateful firewall. Through known attack descriptions, we illustrate the power of the configuration language of the firewall which uses the capability to specify stateful objects that track data from multiple SIP elements within their lifetime. We demonstrate through measurments on a real implementation of the firewall its efficiency and performance.