PBX

An internal telephone switching system, a target for toll fraud.

A Private Branch Exchange is an organization's internal telephone switching system that connects internal extensions and routes calls to external lines. It is a target for toll fraud, where attackers exploit weak configurations or default credentials to place expensive calls at the victim's expense. Modern VoIP-based PBX systems also face eavesdropping and denial of service risks if signaling and media are not secured. Hardening administrative access, disabling unused features, and restricting outbound dialing are common protections.