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

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions 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 FS.11 / FS.19 / FS.20 as a 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.

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