Authentication mechanisms for call control message integrity and origin verification

Abstract

Methodologies developed in the Internet IntroductionAsynchronous transfer mode (ATM) and frame relay (FR) are being deployed extensively as the broadband backbone and Internet protocol (IP) data backhaul, respectively. The purpose of this deployment is to integrate voice and data communications and provide virtual private network (VPN) services to small-and medium-sized business customers. In this context, security and protection mechanisms are integral. Network service providers are utilizing in-band signaling mechanisms, such as ATM user-network interface version 4.0 (UNI 4.0). Inherent in these mechanisms is the danger of bypassing traditional protection mechanisms, such as firewalls, and exposing sensitive information to global public Internet networks. Providers are also employing classical IP over ATM, local area network emulation, or multiprotocol over ATM over global networks.This method of network access from a local IP network into a public ATM or FR backbone involves an entirely new set of threats to the IP infrastructure. While the inherent complexity of ATM and FR protocols makes it difficult to identify all vulnerabilities that may exist and to predict all control plane threats, the following example illustrates one new threat scenario. End system address spoofing provides a simple method for carrying out denial of service and unauthorized information access attacks. Since ATM routing allows multiple routes to a destination, new calls may be routed to the attacker, denying service. Once the call to the attacker is established, the attacker can access the legitimate caller, providing unauthorized access to information. Further, the attacker can force callers to provide their addresses in the call control messages and use this information to spoof their addresses. As a result, security mechanisms at the call control layer are needed to prevent these kinds of attacks.Existing ATM and FR security mechanisms are tunnel based, i.e., they operate on the network layer, providing reliable transport services to the call control layer and provide secure tunnels between physical interfaces. As a result, they will be referred to as