Book Image

Ghidra Software Reverse Engineering for Beginners

By : A. P. David
Book Image

Ghidra Software Reverse Engineering for Beginners

By: A. P. David

Overview of this book

Ghidra, an open source software reverse engineering (SRE) framework created by the NSA research directorate, enables users to analyze compiled code on any platform, whether Linux, Windows, or macOS. This book is a starting point for developers interested in leveraging Ghidra to create patches and extend tool capabilities to meet their cybersecurity needs. You'll begin by installing Ghidra and exploring its features, and gradually learn how to automate reverse engineering tasks using Ghidra plug-ins. You’ll then see how to set up an environment to perform malware analysis using Ghidra and how to use it in the headless mode. As you progress, you’ll use Ghidra scripting to automate the task of identifying vulnerabilities in executable binaries. The book also covers advanced topics such as developing Ghidra plug-ins, developing your own GUI, incorporating new process architectures if needed, and contributing to the Ghidra project. By the end of this Ghidra book, you’ll have developed the skills you need to harness the power of Ghidra for analyzing and avoiding potential vulnerabilities in code and networks.
Table of Contents (20 chapters)
1
Section 1: Introduction to Ghidra
6
Section 2: Reverse Engineering
12
Section 3: Extending Ghidra

Deobfuscating malware samples using scripts

In the previous chapter, we showed how Alina injects shellcode into the explorer.exe process. We analyzed this by simply reading the strings, which is a quick, practical approach, but we can be more accurate in our analysis. Let's focus on some shellcode details.

The delta offset

When injecting code, it is placed in a position that is unknown at development time. As a consequence, the data cannot be accessed by using absolute addresses; instead, it must be accessed via relative positions. The shellcode retrieves the current address at runtime. In other words, it retrieves the EIP register.

The purpose of the EIP register in x86 architecture (32-bit) is to point to the next instruction to execute; so, it controls the flow of a program. It determines the next instruction to execute.

But, as the EIP register is controlled implicitly (by control-transfer instructions, interruptions, and exceptions), it cannot be accessed directly...