Vulnerabilities and the Vulnerability Landscape
Bruce Schneier · 2015
Vulnerabilities are weak links. Finding a security vulnerability is only one step toward exploiting it, though. Getting in a position to exploit the vulnerability, actually exploiting that vulnerability, and then making a getaway are also important, you can't have a successful attack without them. Countermeasures are methods to reduce vulnerabilities. There are three parts to an effective set of countermeasures: protection, detection, and reaction. Most computer-security countermeasures are prophylactic: cryptography, firewalls, passwords. Some are detection mechanisms: intrusion detection systems. The vulnerability landscape can be organized in several ways. It is divided into four broad categories: the physical world, the virtual world, the trust model, and the system's life cycle. Attacks against a physical infrastructure from the virtual world can often be conducted instantaneously and remotely, without warning. They are often much nastier than attacks in the physical world.