1. A method of vulnerability filtering using one or more ontologies of rules, each of the ontologies comprising at least one rule hierarchy comprising one or more vulnerability or weakness scanning rules, the at least one rule hierarchy including priorities that are assigned to at least some of the vulnerability or weakness scanning rules, the method comprising: by a computer, attempting to execute a first one of the vulnerability or weakness scanning rules against a target remote computing device in an order based at least in part on the assigned priorities, producing at least one scan result; based on the at least one scan result, determining that an attempt to execute the first one of the vulnerability or weakness scanning rules against the target remote computing device was unsuccessful; and based on the determining, not executing a scanning rule in the rule hierarchy having a lower assigned priority than the first scanning rule against the target remote computing device.