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PBX Vulnerability Analysis: Finding Holes in Your PBX Before Someone Else Does



David R. Kuhn


This report presents a generic methodology for conducting an analysis of a Private Branch Exchange (PBX) in order to identify security vulnerabilities. The report focuses on digital-based PBXs and addresses the following areas for study: System Architecture; Hardware; Maintenance; Administrative Database/Software; User Features. The methods described in this report are designed to assist administrators in conducting this type of testing. Computer based telephony systems and new techniques such as voice over IP (VoIP) present an entirely new collection of vulnerabilities and are not addressed in this report. However, some of the evaluation methods described here may be applied to these systems as well.
Special Publication (NIST SP) - 800-24
Report Number


computer security, PBX, private branch exchange, telecommunications security


Kuhn, D. (2001), PBX Vulnerability Analysis: Finding Holes in Your PBX Before Someone Else Does, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 24, 2024)
Created April 1, 2001, Updated February 19, 2017