Domain Name System (DNS) is one of the most widely used protocols in the Internet. The main purpose of the DNS protocol is mapping user-friendly domain names to IP addresses. Unfortunately, many cyber criminals deploy the DNS protocol for malicious purposes, such as botnet communications. In this type of attack, the botmasters tunnel communications between the Command and Control (C&C) servers and the bot-infected machines within DNS request and response. Designing an effective approach for botnet detection has been done previously based on specific botnet types Since botnet communications are characterized by different features, botmasters may evade detection methods by modifying some of these features. This research aims to design and implement a multi-staged detection approach for Domain Generation Algorithm (DGA), Fast Flux Service Network, and Domain Flux-based botnets, as well as encrypted DNS tunneled-based botnets using the BRO Network Security Monitor. This approach is able to detect DNS-based botnet communications by relying on analyzing different techniques used for finding the C&C server, as well as encrypting the malicious traffic
