Methods and systems for independent security scrubbing and billing of calls through an IP Multimedia Core Network Subsystem (IMS) are provided. The system includes a core IMS network and a security network cloud securely connected via session border controllers. The IMS network is configured to route calls to the security network cloud. The security network includes call-processing and billing servers that implement security checks on calls from OSI model layer three to seven and analyze the call to collect and generate billing data. After successful security and billing operations, the call is routed back to the IMS network for handling according to conventional workflows. Accordingly, the disclosed invention serves to enhance security for IMS traffic, improve the accuracy of customer billing and conserves IMS network resources which would otherwise be consumed by malicious attacks and billing responsibilities.