What makes a system insecure?

Con una cita que generalmente se le atribuye, Gene Spafford viene al rescate:

The only system which is truly secure is one which is switched off and unplugged, locked in a titanium lined safe, buried in a concrete bunker, and is surrounded by nerve gas and very highly paid armed guards. Even then, I wouldn’t stake my life on it.

Ni que decir tiene que en la práctica, y perdónenme la redundancia, se suele ser un poco más práctico…