Invention selectively enables usage of services and communication conduits in a computer network, wherein the enablement is contingent on usage conditions, resulting in containment of the spread of unauthorized activity within a networked computer system and limiting the scope of results when an element becomes part of a hostile execution environment. Instead of protecting individual networked elements from a potentially hostile execution environment, the elements' usage of the networked environment is restricted to the extent of selectively allowing usage of needed resources explicitly authorized for use by such elements.