1. A method of securing a plurality of virtual networks with a virtualized network security system (VNSS), comprising: providing a plurality of flow processors, each configured as elements of the VNSS for processing a data flow, said data flow being transferred between a first port and a second port of the VNSS, the data flow comprising subscriber profile data; establishing a first security policy for a first virtual network based at least in part on the subscriber profile data included in the data flow; establishing a second security policy for a second virtual network based at least in part on the subscriber profile data included in the data flow; processing the data flow received at said first port for the first and second virtual networks through at least one of the plurality of flow processors, wherein portions of the data flow that are associated with the first virtual network are processed according to the first security policy, and wherein portions of the data flow that are associated with the second virtual network are processed according to the second security policy, said processing further comprising: making a first determination, in accordance with one of the first security policy and the second security policy, of abnormalities that are associated with the data flow, the first determination based at least in part on the subscriber identified by the subscriber profile data; and making a second determination, in accordance with one of the first security policy and the second security policy, based at least in part on the subscriber identified by the subscriber profile data, and transferring said data flow to said second port.