Sensitivity Analysis of an Attack Containment Model

Abstract

A feedback control model has been previously proposed to regulate the number of connections at different levels of a network. This regulation is applied in the presence of a worm attack resulting in a slow down of the spreading worm allowing time to human reaction to properly eliminate the worm in the infected hosts. The feedback model constitutes of two queues, one for safe connections and another for suspected connections. The behavior of the proposed model is based on three input parameters to the model. These parameters are: (i) the portion of new connection requests to be sent to the suspect queue, (ii) the number of requests to be transferred from the suspect to the safe queue, and (iii) the time out value of the requests waiting in the suspect queue. The more we understand the effects of these parameters on the model, the better we can calibrate the model. Based on this necessity, a sensitivity analysis of the model is presented here. The analysis allows for the computation of the effects of changing parameters in the output of the model. In addition, the use of a sensitivity matrix permits the computations of not only changes in one parameter but also combined changes of these parameters. From the sensitivity analysis we have verified our assumption that the changes in the input parameters have no effect on the overall system stability. However, there will be a short period of instability before reaching a stable state.