Specifically, the most financially devastating feature is The Killer Feature: Automated, Untraceable Dialing Once an attacker compromises a PBX (often through default passwords on voicemail or admin portals), they exploit its most legitimate feature: the ability to make outbound calls over SIP trunks.
That is an intriguing term. While "PBX attack" isn't a single, standardized piece of hacking software, it refers to a . pbx attack
Here is the most "interesting" feature of a PBX attack: standardized piece of hacking software
A PBX that has unlimited international calling but no outbound call alerts or per-call spending limits . pbx attack