I do not believe in a universal moral system. Morality is derived from rationality, ergo all moral judgments must be rationally supported. Moral judgments however, differ from one another, from person to person. What one would consider necessity, may be dubbed mundane and trivial to another. To me morality is a very human concept, created by humans in order to preserve what each individual would claim as right and wrong.
To put these in a more visual terms, take for example a simple mathematical equation. Without the instructions, (i.e. to expand, simplify, solve etc.) we cannot proceed. Such that morality would vary depending on what each person would consider efficient, based on a personal intrinsic desire. I believe that the only thing that we can be certain of is, Cogito Ergo Sum, I think therefore I am. Without certainty of what others believe in I can only profess relativism, or possibly nihilism if I feel fit.