SeMS may be defined as a formal, risk-driven method of integrating security into an organization. This methodology requires coordination of activities, responsibilities, practices, procedures, processes and resources (i.e. it has to be Systematic, Proactive and Explicit).
In more ordinary words, SeMS is a holistic approach to security striving to move from a classical (reactive) perspective to a more proactive and predictive one. It moves away from a “one size fits all” to a more tailored system. Still, restrictive baseline measures may be necessary, but flexibility should be allowed in the system to let it adapt itself to cope with the specific threats and security needs of an organization.