CVE-2025-5548 – FreeFloat FTP Server 1.0 Walkthrough

Repository where we document step by step the analysis and controlled exploitation of CVE-2025-5548 on FreeFloat FTP Server 1.0 within a laboratory environment.

In this project we do not limit ourselves to running a pre-made exploit. Our goal is to build and document a complete technical process: we prepare the environment, reproduce the fault, analyze the vulnerability, identify the necessary elements for exploitation, and develop a functional proof of concept in a progressive and justified manner.

Project Objective

With this repository we aim to:

• document clearly and in a structured way how we approach the controlled exploitation of CVE-2025-5548;
• reflect a reproducible working methodology in a vulnerability analysis laboratory;
• justify each phase of the process, from environment preparation to final validation;
• generate useful documentation both for academic delivery and for a technical portfolio.

Scope

In this work we focus on a practical case based on FreeFloat FTP Server 1.0, with special attention to the step-by-step analysis and exploitation process.

The scope of the project includes:

• preparation of the laboratory environment;
• installation and configuration of the necessary tools;
• identification and study of the vulnerability;
• progressive development of the exploitation process;
• technical validation of the results;
• complete documentation of the followed flow.

We do not aim to present this case as an unprecedented vulnerability nor as offensive development oriented towards real-world environments. We approach it as a controlled technical practice, for educational and professional documentation purposes.

Context of the Practice

This practice is part of an activity oriented towards vulnerability analysis and exploitation, in which we must demonstrate not only that we know how to follow a guide, but that we are capable of understanding the process, justifying technical decisions, and recording them professionally.

For this reason, this repository does not merely show the final result. It also collects the reasoning, intermediate checks, observations made during the lab, and conclusions drawn from the case.

Reference Repository

To guide the development of this practice we have taken the following base repository as a reference, used as support to follow the general lab flow:

• Reference repository on CVE-2025-5548

Based on that material, in this project we reproduce the case in our own lab environment, validate each phase with our own tests, and document the process in a structured way, incorporating evidence, observations, and our own technical decisions.

Work Approach

To develop this practice we follow a progressive approach. First we set up the environment. Then we verify the vulnerable behavior of the application and, from there, advance through the different usual phases in an exploitation process:

1. reconnaissance of the environment and the vulnerable application;
2. reproduction of the fault;
3. analysis of the overflow;
4. identification of the offset;
5. verification of execution flow control;
6. bad characters analysis;
7. location of useful addresses;
8. construction and validation of the final exploit.

In this way, each step is connected to the next and we can technically justify why we perform each check.

Laboratory Environment

This repository documents a controlled laboratory environment. We will detail precisely the versions, tools and configurations used.

Environment Base

• Laboratory operating system: [pending to complete]
• Vulnerable application: FreeFloat FTP Server 1.0
• Language used for scripts: Python
• Auxiliary tools: [pending to complete]
• Debugger used: [pending to complete]

Repository Structure

The repository structure is organized to separate documentation, scripts, screenshots and technical notes:

├─ README.md
├─ docs/
│  ├─ 01-introduccion-y-objetivo.md
│  ├─ 02-entorno-de-laboratorio.md
│  ├─ 03-instalacion-y-preparacion.md
│  ├─ 04-analisis-de-la-vulnerabilidad.md
│  ├─ 05-explotacion-paso-a-paso.md
│  └─ 06-conclusiones.md
├─ images/
│  ├─ crash_debugger.png
│  ├─ ftp server.png
│  ├─ funcion_relevante.png
│  ├─ ghidra.png
│  ├─ ida.png
│  ├─ immunity debugger.png
│  ├─ mona.png
│  ├─ notepad++.png
│  ├─ proceso_debugger.png
│  ├─ pycharm.png
│  ├─ strings_xrefs.png
│  └─ visual studio code.png
└─ scripts/
   ├─ 01Python3Connection.py
   ├─ 02Python3Fuzzing.py
   ├─ 03Python3EIPOffsetDiscovery.py
   ├─ 04Python3ControlEIP.py
   ├─ 05Python3FindBadChars.py
   └─ 06Python3JMPESP.py

Repository Content

docs/

Here we centralize the main documentation of the project. Each file develops a specific phase of the lab so that the process stays organized and easy to follow.

scripts/

Here we include the scripts used during the practice. The idea is to keep both the evolution of the process and the final version of the proof of concept.

images/

Here we store screenshots from the lab: installation, configuration, vulnerable behavior, debugger, validations and final result.

Methodology We Follow in This Project

Throughout the repository we document a practical methodology based on these principles:

• do not advance to the next step without validating the previous one;
• record evidence of each phase;
• technically justify each change introduced in the scripts;
• clearly separate observation, analysis and exploitation;
• keep the work reproducible within the lab.

This approach allows us to turn an exploitation practice into useful and reviewable technical documentation.

Project Status

We are currently working on:

• environment preparation;
• initial repository organization;
• writing the base documentation;
• gradual incorporation of scripts, screenshots and validations.

Responsible Use and Ethical Scope

All content in this repository is developed and documented exclusively in a controlled laboratory environment, for educational, academic and technical learning purposes.

We do not orient this project towards use on third-party systems or unauthorized contexts. The goal is to study the vulnerability, understand its exploitation in a controlled scenario and document the process professionally.

Next Steps

The next steps of the project will be:

• complete the detailed description of the environment;
• document the installation and preparation of the tools;
• record the technical analysis of the vulnerability;
• develop and validate the exploit step by step;
• close the repository with conclusions and references.

Authorship

Repository developed as a technical practice on vulnerability analysis and exploitation, with a step-by-step documentation approach and portfolio orientation.

Author: Àngels Gumbau Granero