What role does SBC security play in VoIP protection?

The endless growth of voice over IP in business networks has resulted in growing deployment and importance of enterprise session border controllers. As SBCs and Session Initiation Protocol-based communications become more prominent, SBC security becomes increasingly important.

Some SBCs are implemented as functions in a virtual machine or container, either on premises or in a public cloud, rather than as stand-alone appliances. This deployment model offers additional challenges, as deployments might have to handle more security functions and may be at risk of greater exposure to SBC security attacks on their platforms.

Security has always been a feature category for SBCs. But, as with most products, different vendors place differing amounts of importance on specific features. If there is an essential SBC security feature, however, it's denial-of-service (DoS) protection.

Given that the SBC is at the edge of the network, typically bordering a public network, it is exposed to DoS attacks. Those attacks could be the garden-variety IP attacks, such as ping of death or TCP SYN flooding that attempts to deny service by flooding the IP stack, or more sophisticated attacks specifically aimed at SBCs.

An attack aimed specifically at SBCs might consist of Session Initiation Protocol signaling and registration overloads. So, expect DoS attack SBC security protection to evolve and become more sophisticated to keep up with -- and hopefully ahead of -- the attackers.

Keeping unauthorized users out of the SBC system is an important consideration. Configuration security can be enhanced when SBCs provide access control lists and URL filtering that limit device access to specified users and IP addresses.

Let's not forget the voice-over-IP service itself is a valuable resource. Some companies extend their SBC security umbrella to include validation of media and signaling to prevent theft of service.

Finally, SBCs running in virtualized containers may have additional security challenges, as an attack on the container -- be it VMware, Kubernetes or others -- can affect the SBC app. The same type of DoS attacks and administrative intrusions are security issues that affect the SBC, but over which the SBC has little control.

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