A lot of industries or power plants are using multicriteria models to improve the management of their safety and security systems. But most of the accidents that occur are due to technical failures or human errors and find rarely their origins in intentional malevolent acts, more unpredictable. After having established a wide scope of necessity to define a complete framework including multicriteria applications to face up various threats of agressions, we noticed that current targets are infrastructures receiving sport events, and particularly football stadiums. So, we have developped an entire process associated to a software wich permits to assess and represent vulnerabilities around those complex systems. The final result provides to the safety manager a dynamic and decisional tool. It is then possible to efficiently build and optimize the security system according to real needs at a given moment by confronting potential attacks and various responses choosen among a list of appropriated options of prevention and protection.