PBX (Private Branch Exchange)

A Private Branch Exchange is a private telephone switch installed at a business, providing internal extensions and shared access to outside lines. Modern IP PBXs (often based on Asterisk, FreeSWITCH, or vendor systems) connect via SIP trunks. Insecure PBX configurations, default credentials, exposed SIP ports, weak voicemail PINs, are a leading cause of toll fraud worldwide.

Categories: Radio Access NetworkSignalingFraud

PBX in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Signaling protocols carry the control-plane messages that set up calls, register subscribers and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA as top-tier telecom risk.

To place PBX in the wider telecom-security picture, review PBX Hacking, Blue Team, Media Gateway, GSMA Open Gateway, PSTN and GRX: each entry cross-references back to this page so you can walk the topic in either direction.

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