  The paper examines quantitative assessment of wireless distribution system
security, as well as an assessment of risks from attacks and security
violations. Furthermore, it describes typical security breach and formal attack
models and five methods for assessing security. The proposed normalized method
for assessing the degree of security assurance operates with at least three
characteristics, which allows comparatively analyze heterogeneous information
systems. The improved calculating formulas have been proposed for two security
assessment methods, and the elements of functional-cost analysis have been
applied to calculate the degree of security. To check the results of the
analysis, the coefficient of concordance was calculated, which gives
opportunity to determine the quality of expert assessment. The simultaneous use
of several models to describe attacks and the effectiveness of countering them
allows us to create a comprehensive approach to countering modern security
threats to information networks at the commercial enterprises and critical
infrastructure facilities.
