VoIP Infrastructure Security

How secure is your VoIP Deployment?

There are lots of approaches to securing VoIP networks including the deployment of firewalls,
Session Border Controllers (SBC), encrypting SIP with TLS and voice with SRTP. But have you ever
considered an attack from the inside and in particular the integrity of the firmware running on each
IP Phone? If not I strongly recommend taking 55 minutes to watch the following on YouTube: