How to Cheat at VoIP Security
If VoIP engineering is not your specialty, this guide provides an introduction to VoIP security, and covers exploit tools and how they can be used against VoIP systems.
TABLE OF CONTENTS How to Cheat at VoIP Security
SIP Functions and Features
When SIP was developed, it was designed to support five specific elements of setting up and tearing down communication sessions. These supported facets of the protocol are:
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User location, where the endpoint of a session can be identified and found, so that a session can be established
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User availability, where the participant that s being called has the opportunity and ability to indicate whether he or she wishes to engage in the communication
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User capabilities, where the media that will be used in the communication is established, and the parameters of that media are agreed upon
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Session setup, where the parameters of the session are negotiated and established
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Session management, where the parameters of the session are modified, data is transferred, services are invoked, and the session is terminated
Although these are only a few of the issues needed to connect parties together so they can communicate, they are important ones that SIP is designed to address. However, beyond these functions, SIP uses other protocols to perform tasks necessary that allow participants to communicate with each other, which we ll discuss later in this chapter.
User Location
The ability to find the location of a user requires being able to translate a participant s username to their current IP address of the computer being used. The reason this is so important is because the user may be using different computers, or (if DHCP is used) may have different IP addresses to identify the computer...
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