CyberSecurity & DevSecOps Expert: Develop, PenTest, and Deploy Secure Applications

Linux is a multi-user operating system, which means that multiple users can work on the same machine simultaneously or sequentially. To ensure that each user can only access what they are entitled to — and nothing more — Linux relies on a system of p...

THEORETICAL RECAP In Linux, copying, moving, and deleting files are everyday operations — but in a security context, each action carries real risk. The commands cp, mv, and rm are powerful and unforgiving: there is no Recycle Bin, no undo, and no pro...

Now that you have a solid understanding of how to navigate the Linux file system — using commands like cd, pwd, ls, and tree — and that you understand the overall hierarchy of directories on a Linux system, it is time to move on to the next essential...

Understanding the Linux file system hierarchy is a fundamental skill for anyone working in cybersecurity or system administration. You have already practiced navigating the file system using commands like pwd, ls, cd, and tree. Now it is time to unde...

THEORETICAL RECAP The `tree` command is a Linux utility that recursively displays the directory structure of a filesystem path in a visual, hierarchical format — much like a branching diagram. Unlike `ls`, which only lists the immediate contents of a...

Now that you have learned the foundational Linux commands — pwd, ls, cd, and how to interpret paths — it is time to go deeper. Mastering navigation in a Linux terminal is not just about knowing the commands. It is about understanding the subtle mista...

**Theoretical Recap** Navigating the Linux filesystem is a foundational skill for any security professional. Every file and directory in Linux lives within a single hierarchical tree rooted at /. Understanding how to move through this tree efficientl...

**Theoretical Recap** Before diving into the hands-on tasks, let's consolidate the key concepts from the previous lesson on Linux terminal fundamentals. The Linux terminal (also called the shell or command-line interface) is your primary tool as a se...

The Linux terminal is one of the most powerful and essential tools in cybersecurity and DevSecOps practice. Unlike graphical interfaces, the terminal gives you direct, precise, and scriptable control over a system. Understanding how it works, what it...

Welcome to the chapter 'Operating systems: Linux advanced for security', part of the course 'CyberSecurity & DevSecOps Expert: Develop, PenTest, and Deploy Secure Applications'. This chapter is designed for learners who are at a beginner level in Lin...

## Project Overview This final mini-project consolidates everything you have practiced throughout the chapter: port scanning with Nmap, HTTP header analysis with the Requests library, date/timestamp manipulation, output formatting (text, CSV, JSON), ...

THEORETICAL RECAP Secure scripting best practices are not optional additions — they are the foundation of any professional automation script, especially in a security context. When you write a Python script intended for security tasks, several non-ne...

When you write Python scripts for security automation — whether for port scanning, HTTP analysis, report generation, or any other task you have already practiced — you are not just writing code that works. You are writing code that will run in sensit...

**Theoretical Recap** The X-Frame-Options HTTP response header is a security mechanism that instructs the browser whether or not a web page can be embedded inside an , , , or element. It is a first line of defense against Clickjacking attacks, where ...

The Requests library is one of the most widely used Python libraries for making HTTP (HyperText Transfer Protocol) requests. In a cybersecurity and automation context, it allows you to interact programmatically with web servers and web application pr...

In cybersecurity and DevSecOps work, generating structured and readable reports is a critical skill. After scanning ports, extracting IP addresses from logs, or running an Nmap wrapper like you did in your mini-project, the raw data collected must be...

## Mini-project: Nmap Wrapper — Runtime & XML Capture ### Project Overview In this first mini-project step, you will build a Python wrapper around the Nmap network scanner. Rather than running Nmap manually from the terminal, your script will launch ...

When working in cybersecurity automation, one of the most critical and recurring tasks is reading, parsing, and comparing dates and timestamps found in log files. Whether you are analyzing an Apache web server log, a firewall alert log, a system auth...

**Theoretical Recap** A port scanner is one of the most fundamental tools in a security professional's toolkit. In networking, a port is a logical endpoint for communication, identified by a number from 0 to 65535. When you attempt to connect to a po...

A socket is a programming interface that allows two machines — or two processes — to communicate over a network. Think of it as a telephone plug: it allows a connection to be established between a sender and a receiver. In the world of networks, ever...

**Theoretical Recap** A regular expression (regex) is a sequence of characters that defines a search pattern. In Python, the `re` module provides all the tools needed to apply these patterns to strings. The key functions to know are: `re.findall()` w...

Regular expressions are one of the most powerful tools available to a security automation specialist. They allow you to search, identify, extract, and manipulate text based on patterns rather than fixed strings. In cybersecurity, this capability is i...

**Theoretical Recap** A dictionary in Python is a data structure that stores key-value pairs, where each key is unique. Unlike lists, which use integer indices, dictionaries use meaningful keys to access values instantly — making them ideal for mappi...

**Theoretical Recap** In Python, a list is an ordered, mutable collection of items defined with square brackets: `my_list = [80, 443, 22, 8080]`. Lists are one of the most fundamental data structures you will use in security automation — for example,...

In the previous activities, you worked with variables that stored a single value at a time: a string, a number, or a boolean. In real-world cybersecurity and automation work, you will almost always need to handle collections of data. For example, you...