Shellcodes, Backdoors, Droppers, and Worms

by David Martínez Oliveira, aka Pico

Download Chapter 3: Spell of Rebirth: Transmuting Greetings Into Shellcode

In hacker circles, heavy wizardry means code that trades on intimate knowledge of a system—the kind that speaks its private dialects and bends its rules. Heavy Wizardry 101 teaches you to write it. You’ll build shellcode, backdoors, droppers, and worms from scratch, working at the instruction level where magic happens.

Every project is implemented for four architectures: x86_64, ARM, MIPS, and RISC-V. You’ll write the same program four times, seeing exactly what stays constant and what changes. Each chapter starts with architecture fundamentals, such as memory layout, calling conventions, and stack mechanics, then walks through complete working implementations on Linux in safe, contained environments.

Learn to:

• Write position-independent shellcode and programs that execute in constrained memory spaces
• Implement TCP reverse shells that bypass basic network restrictions
• Build executable droppers that embed and deploy payloads without detection
• Create self-replicating worms that propagate across networked systems
• Write basic port scanners to discover services in a network
• Port low-level code between architectures by understanding instruction-level differences

Whether you’re a penetration tester who wants to stop depending on Metasploit, a security researcher analyzing malware, or a systems programmer who needs to understand how computers work, this book gives you the skills to build and reason about code at the lowest level.

Author Bio 

David Martínez Oliveira, aka Pico, has been writing code close to the metal since the 1990s, building software for computer vision, communications systems, laboratory equipment, and AR/VR/MR applications. A longtime GNU/Linux user, he explores security and low-level system internals both professionally and for fun.

Table of contents 

Reviews 

"Heavy Wizardry 101 is a well-organized and accessible introduction to low-level programming in assembly for Linux, crafting multi-stage shellcode loaders, network and binary tools, and ELF binaries using only standard, open-source GNU command-line tools."
—Sergi Àlvarez i Capilla (aka pancake), Author of radare2