Attaching a packet capture tool or protocol analyzer to the VoIP network segment enables easy interception of voice traffic.
NIST recommendation
Establish good physical security policy for the deployment environment to prevent attachment of a packet capture tool or protocol analyzer to the VoIP network segment. Disable the hubs on IP Phones and use an alarm system for notifying the administrator when an IP telephone has been disconnected so that the system will not be open to this kind of attack.
How Messaging addresses the vulnerability
Messaging logs events such as the disconnect of an IP telephone are reported to Messaging. In addition, an alarm is generated when an IP telephone is disconnected. See Maintenance Commands for Avaya Servers, and Media Gateways, 03-300430