🧠 CrackMe Challenge – "Remove the Nag" by TDC

This repository contains my reverse engineering walkthrough and patch for the classic CrackMe challenge by The Dutch Cracker (TDC).

📚 Part of my coursework for Malware Analysis and Cyber Defence
🛠️ Reverse engineered and patched in under 12 hours
✨ Goal: Turn a nagging binary into a grateful one

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🎯 Objectives

• Remove the nag screen at startup
• Make the "Re-Check" button display:
  "Thank you for registering this software"
• Change the status box to:
  "Clean crack! Good Job!"

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🗂️ Repository Structure

remove-the-nag-by-tdc/
├── README.md                 # You're reading this!
├── RemoveTheNag.7z           # Original CrackMe binary (unmodified)
├── patch_notes.md            # Patch strategy and byte-level summary
├── screenshots/              # Before/after snapshots from IDA
│   ├── before_patch.png
│   └── after_patch.png
└── patched_binary.exe       # Patched binary if legally shareable

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📖 Write-Up

👉 Read the full Medium article for a fun and philosophical breakdown:
🔗 https://medium.com/

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⚠️ Disclaimer

This repository is for educational purposes only.
No copyrighted or malicious software is included or distributed.
Reverse engineering was performed on a publicly available CrackMe intended for legal, academic learning.

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🧠 Key Learnings

• 🌀 Don’t trust shiny strings — they distract
• 🖱️ GUI apps need interaction — click before you hack
• 📊 Global variables are the heartbeat of binary state
• 🧘‍♂️ Reverse engineering is about listening, not brute-forcing

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🧰 Tools Used

• IDA Free 8.3
• HxD Hex Editor
• Windows 10 VM (FlareVM)

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Happy reversing! 🎯