Cyberwar: The Next Threat to National Security & What to Do About It

by Richard A. Clarke

The most common software error for years, and one of the easiest to explain, is something called “buffer overflow.” Code for a webpage is supposed to be written in such a way that when a user comes to that webpage, the user can only enter a certain amount of data, like a user name and password. It’s supposed to be like Twitter, a program where you can enter, say, no more than 140 characters. But if the code writer forgets to put in the symbols that limit the number of characters, then a user can put in more. Instead of just putting in a user name or password, you could enter entire lines of instruction code. Maybe you enter instructions to allow you to add an account. Think about those instructions overflowing the limited area where a public user is supposed to be able to add information and then those instructions falling into the application. The instruction code reads as if a systems administrator had entered it and—ping!—you are inside.