Telecom stacks are full of questionable security decisions, some stemming from the protocol level. Protocols like SS7 were designed without any concept of hacke

Telecom stacks are full of questionable security decisions, some stemming from the protocol level. Protocols like SS7 were designed without any concept of hackers or malicious actors. You can slap firewalls on top of them, but those interfere with desired functionality and even if they don't they require extra investment. DIAMETER is better but still full of holes. Security in the telecom space has been a point of priority for the past couple of years and things are improving, but there are decades of legacy hardware, software, firmware, and network designs to cover for. I doubt anyone is running standard Freeswitch in their telco networks, but the problems Freeswitch has as an aging telecom product with a history of not looking for security as much as one might expect those are all over the place.