Book Image

Network Protocols for Security Professionals

By : Yoram Orzach, Deepanshu Khanna
5 (1)
Book Image

Network Protocols for Security Professionals

5 (1)
By: Yoram Orzach, Deepanshu Khanna

Overview of this book

With the increased demand for computer systems and the ever-evolving internet, network security now plays an even bigger role in securing IT infrastructures against attacks. Equipped with the knowledge of how to find vulnerabilities and infiltrate organizations through their networks, you’ll be able to think like a hacker and safeguard your organization’s network and networking devices. Network Protocols for Security Professionals will show you how. This comprehensive guide gradually increases in complexity, taking you from the basics to advanced concepts. Starting with the structure of data network protocols, devices, and breaches, you’ll become familiar with attacking tools and scripts that take advantage of these breaches. Once you’ve covered the basics, you’ll learn about attacks that target networks and network devices. Your learning journey will get more exciting as you perform eavesdropping, learn data analysis, and use behavior analysis for network forensics. As you progress, you’ll develop a thorough understanding of network protocols and how to use methods and tools you learned in the previous parts to attack and protect these protocols. By the end of this network security book, you’ll be well versed in network protocol security and security countermeasures to protect network protocols.
Table of Contents (23 chapters)
Part 1: Protecting the Network – Technologies, Protocols, Vulnerabilities, and Tools
Part 2: Network, Network Devices, and Traffic Analysis-Based Attacks
Part 3: Network Protocols – How to Attack and How to Protect

Using DNS to bypass network controls – DNS tunneling

Often in organizations, outbound access is not allowed or is allowed only via HTTPS via proxy servers. But regardless of how strict the firewall rules and Access Control Lists (ACLs) are set, DNS requests are usually allowed through the firewalls. Attackers can abuse these misconfigured DNS service rules by creating a tunnel directly through compromised workstations or servers to exfiltrate confidential data to their servers, hosted externally on the internet.

This approach is similar to other tunneling protocols such as HTTP, HTTPS, TCP, and so on, but here, the protocol is DNS and the transmission channel is UDP.

To create a tunnel, we need a handler and a DNS server to communicate from the internal network of the organization and exfiltrate a good amount of data, without missing a single packet because of congestion or connection breaks in between and without getting detected. To achieve this, there are numerous...