Security issues in SS7 signaling networks

The last few years have seen a rapid integration of voice and data services and an almost universal adoption of migration plans to Voice over Packet infrastructures. This has led to a distributed deployment of hardware and software platforms that interconnect to the traditionally semi-isolated SS7 signaling networks. This paper examines the threats to the signaling network at the SS7 protocol level. It focuses on the MTP3 and SCCP layer transactions. SS7 attacks can be classified as either active or passive. We identify those messages that can most effectively compromise an SS7-based network. In particular, we detail the MTP3 and SCCP messages and relevant parameters, and show how making small changes in those parameters can lead to various levels of service disruption.