Vulnerabilities and the Vulnerability Landscape
In Part 1 we looked at attacks in theory: what kinds of attacks there are and what kinds of attackers there are. But as I have said elsewhere, there is a difference between theory and practice. As anyone who reads mystery novels or newspaper crime reports knows, there is a lot more to an attack than simply finding a vulnerability. In order to successfully make use of that vulnerability, the attacker has to find a target, plan the attack, do the deed, and get away. A vulnerability in a safe's locking mechanism, if that safe is hidden in a secret location, is not as serious as the same vulnerability in a bank's night-deposit box.
It's no different in the digital world. It's not enough for a potential criminal to find a flaw in the encryption algorithm for the ATM network. He has to get access to the communications line, know enough about the protocols to create a bogus message letting him steal money, actually steal the money, and get away with the crime. Without those other steps, the encryption flaw is just of theoretical value.
Similarly, there is a lot more to a countermeasure than simply throwing a piece of technology at the problem. That vulnerability in the safe could be fixed by installing a stronger lock, or putting alarms on the doors and windows of the room the safe is in and keeping a phalanx of guards nearby. The encryption vulnerability could be fixed with a better encryption algorithm, or by keeping the protocols secret, ...