A simple flaw allowed an anonymous hacker to compromise 50 million Facebook accounts. The flaw involved the ability to preview birthday videos as someone else using Facebook’s “View As” function. Logical errors, sometimes called design flaws, are flaws in code that allow users to take unwanted actions because they weren’t foreseen by the original developers. The worst part is that finding logic errors can’t be solved with automated tools alone. The best advice on how to avoid logic errors comes from Aristotle: “Knowing yourself is the beginning of all wisdom””]