Abstract
In the present study, an extended classification of Internet users penetrating in computer networks and a definition of the motivation as a psychological and emotional state and main prerequisites for modelling of network intruder’s activity are suggested. A mathematical model as a quadratic function of malicious individual’s behavior and impact on the computer network based on three quantified factors, motivation, satisfaction and system protection is developed. Numerical simulation experiments of the unauthorized access and its effect onto the computer network are carried out. The obtained results are graphically illustrated and discussed.