After defining Societal Technological Systems (STS) as a class of systems intended to improve the economy, the security, the health and the environment (the well-being) in human societies, and Intentional Disturbance Actions (IDA) as the planned activities intended to weaken or to interrupt the appropriate management and/or performance of such systems, the author investigates the relationship between System Societal Value (SSV), System Exogenous Support (SES) and System Redundancy Level (SRL). A risk assessment is effected concerning to the risk of eventual degradation of System Societal Value, and the System Redundancy Level is selected as a management tool for the mitigation of such a risk. The transfer between Exogenous Support and Redundancy Level is adopted as a procedure for optimizing resources allocation. Finally, the sensitivity characteristics of this relationship and the main proprieties of its optimal configuration are considered.