Network Security Through Data Analysis, 2nd Edition

Chapter 7. Data and Sensors in the Active Domain

In this chapter, we will discuss the active domain. Active domain data refers to data that the analyst specifically initiates the generation and collection of. Active data will involve the use of probing tools (e.g., ping, traceroute) and scanners (e.g., nmap). It is polled and triggered; as opposed to the continuous collection of the network and service domains, active analysis is done as a specific event or in response to specific anomalies.

Active work is client-focused, informative, and expensive. The analyst takes on the perspective of a client of an application (or, alternatively, an attacker) and is able to gather a lot of information about what a host does, although not necessarily much about what the host is for. But this fine-grained information doesn’t come cheaply; intensive scanning is expensive, it interferes with the target, and it can take an enormous amount of resources to process all the data received.

Chapters related to this one include Chapter 2, on the basics of network traffic, Chapter 13, which discusses the observation of fumbling, and Chapter 17, which is about the use of threat intelligence data.

Discovery, Assessment, and Maintenance

The foundation of operational information security is inventory management. The less you know about the assets you’re protecting—both what they are and what they’re for—the more any security plan is filled with guesswork. Some amount of guesswork is inevitable; networks ...