IEEE 802.1x is a protocol used to control access to LAN services via a network access switchport or wireless access point that requires a device or user to authenticate to the network element and become authorized by the authentication server before accessing the network. This standard is used to activate the network access switchport limiting traffic to a specific VLAN or install traffic filters. Implementing 802.1x port security on each access switchport denies all other MAC users, which eliminates the security risk of additional users attaching to a switch to bypass authentication. The hardware Enterprise Voice, Video, and Messaging Endpoint must be an 802.1x supplicant and integrate into the 802.1x access control system. When 802.1x is used, all devices connecting to the LAN are required to use 802.1x.
An Enterprise Voice, Video, and Messaging Endpoint with a PC port may break 802.1x LAN access control mechanisms when the network access switchport is authorized during the Enterprise Voice, Video, and Messaging Endpoint authentication to the network. This condition may permit devices connected to the PC port to access the LAN. The access switchport can be configured in one of the following modes: single-host, multi-host, or multi-domain. Single-host allows only one device to authenticate, and only packets from this devices MAC address will be allowed, dropping all other packets. Multi-host mode requires one host to authenticate but once this is done, all packets regardless of source MAC address will be allowed. For both the PC attached to the PC port and the Enterprise Voice, Video, and Messaging Endpoint to authenticate separately, multi-domain authentication on the access switchport must be configured. This divides the switchport into a data and a voice domain. In this case if more than one device attempts authorization on either the voice or the data domain of a port, the switchport goes into an error disable state. Disabling the PC port requires the network access switchports are configured with the appropriate VLAN for the VVoIP or VTC traffic and placing the disabled PC port traffic on the unused VLAN. MAC Address Bypass (MAB) is a possible mitigation for this vulnerability. |