Is VoIP secure?

Yes, when properly configured, VoIP is secure, but "VoIP" isn't one single security posture, it depends heavily on how the specific platform and connection are set up. A poorly configured VoIP system genuinely can be less secure than a traditional analogue line; a properly configured one is generally more secure, since it comes with modern encryption tools an old copper line never had.

What Makes VoIP Genuinely Secure

• Encrypted signalling, the setup and control of a call (who's calling whom, when it starts and ends) should be encrypted using TLS, preventing eavesdroppers on the network path from seeing call metadata
• Encrypted media, the actual voice audio itself should be encrypted using SRTP, so even if someone intercepted the network traffic, the conversation content isn't readable
• Strong authentication, extensions and trunks should require strong, unique credentials, not default or shared passwords, since weak credentials are the most common way VoIP systems get compromised
• Network segmentation, voice traffic ideally sits on its own VLAN, separated from general office data traffic, limiting what an attacker could reach even if they compromised something else on the network

What Actually Goes Wrong

The most common real-world VoIP security incidents aren't sophisticated eavesdropping attacks, they're toll fraud: an attacker finds a poorly secured extension or trunk (often using weak or default passwords) and uses it to place expensive international calls at the business's expense, sometimes running up enormous bills overnight before anyone notices. This is entirely preventable with proper authentication, rate limiting, and monitoring, but it's a real and costly risk on an unmanaged, poorly secured system.

Confirming Your Own Setup

If you're evaluating or already running a VoIP system, it's worth directly asking your provider: is signalling encrypted with TLS, is media encrypted with SRTP, and is this the default configuration or something you have to specifically request and pay more for? A provider that can't answer these clearly, or where encryption is an optional extra, is worth treating cautiously.

How This Compares to Traditional Phone Lines

It's worth remembering that traditional analogue and ISDN lines were never encrypted at all, physical access to the right cable was historically enough to listen in. Properly configured VoIP is, in a meaningful sense, more secure than the traditional lines it replaces, precisely because encryption is achievable and increasingly standard on modern platforms in a way it never was on copper.

Our Approach

Every hosted PBX deployment we run includes TLS signalling encryption and SRTP media encryption as standard, not an optional add-on, alongside strong credential policies and monitoring for unusual call patterns that could indicate toll fraud. Security on the voice platform is treated with the same seriousness as security on your data network, because increasingly it's the same network.