Book Image

Mastering Defensive Security

By : Cesar Bravo
Book Image

Mastering Defensive Security

By: Cesar Bravo

Overview of this book

Every organization has its own data and digital assets that need to be protected against an ever-growing threat landscape that compromises the availability, integrity, and confidentiality of crucial data. Therefore, it is important to train professionals in the latest defensive security skills and tools to secure them. Mastering Defensive Security provides you with in-depth knowledge of the latest cybersecurity threats along with the best tools and techniques needed to keep your infrastructure secure. The book begins by establishing a strong foundation of cybersecurity concepts and advances to explore the latest security technologies such as Wireshark, Damn Vulnerable Web App (DVWA), Burp Suite, OpenVAS, and Nmap, hardware threats such as a weaponized Raspberry Pi, and hardening techniques for Unix, Windows, web applications, and cloud infrastructures. As you make progress through the chapters, you'll get to grips with several advanced techniques such as malware analysis, security automation, computer forensics, and vulnerability assessment, which will help you to leverage pentesting for security. By the end of this book, you'll have become familiar with creating your own defensive security tools using IoT devices and developed advanced defensive security skills.
Table of Contents (23 chapters)
Section 1: Mastering Defensive Security Concepts
Section 2: Applying Defensive Security
Section 3: Deep Dive into Defensive Security

Applying secure file permissions

Unix systems have a unique way to manage permissions, which is quite different from Windows systems, so let's start with the basics about how permissions work in Unix systems.

Understanding ownership and permissions

Unix systems have three levels of file/folder ownership and this can be checked with the ls –l command.

As seen in the following figure, the command shows us a lot of information such as hard links, who created the file, the file size, the last modification, and the name of the file or folder, and the most important part of ls is the permissions:

Figure 7.7 – Results of the long listing of files (ls -l)

Now, let's take a look at the permissions section, as seen in the following figure. The first section is the type of the file (in this example we have d for directory or folder).

The other types are as follows:

  • -: Regular file with different extensions such as .txt, .php...