Effective Ways to Protect SIP Connections

Session Initiation Protocol (SIP) is the underlying standard that governs how devices communicate over the Internet. Like most security issues, a defense-in-depth strategy is necessary to protect SIP. That way, even if one security layer fails, another layer is there to provide protection. Next, let's look at a few technologies that can make SIP connections more secure:

1. TLS 1.3. Transport Layer Security (TLS) is a cryptographic protocol used to protect data exchanged over computer networks, and more specifically, TLS is used to protect web user data from cyberattacks. TLS 1.3 is the latest version of this cryptographic protocol and strengthens the algorithm used to encrypt Internet traffic. Check your SIP infrastructure to determine the version your network uses. To provide backward compatibility, many products use TLS 1.2 by default. Where possible, upgrade to TLS 1.3 (it should be a free upgrade) for enhanced session-level security.

2. Firewall. Don’t forget this first line of defense. Contact your security administrator to review your firewall port configuration to ensure you have the protection you need. If you have a next-generation firewall, determine if you can enable Denial of Service (DoS) protection for the SIP ports.

3. Integrated SIP firewall. Some SIP gateways (usually higher-end systems) have SIP security built in. These gateways won't replace a firewall, of course, but they may have supplemental features that can support an existing firewall. Likewise, remember to look for DoS capabilities, as this type of protection is unlikely to be available with a traditional firewall.

4. Theft of Service (ToS) Analysis . It is critical to protect SIP by protecting your SIP environment from theft of service (ToS). If an unauthorized threat actor compromises your system to make their own voice calls over IP Calling, this additional burden can result in poor voice quality and performance that can impact legitimate users. Perform regular security analysis—at least quarterly—to review call and usage logs from your SIP gateways. Calls from all over the world that have no business connection with your company could be linked to a security breach. Finally, do not use default administrator credentials on the gateway. These could be used by unauthorized individuals to compromise the security of the SIP gateway.