MC 4 (Dynamic Analysis)

Platform: CUSTOM | Category: Reversing | Type: Challenge | Difficulty: Easy | OS: N/A | **Author: XESXOR Techniques: filesystem_check_analysis, string_extraction

Summary

Walkthrough of the CUSTOM Reversing MC 4 (Dynamic Analysis). Language: C. Binary only. "Do you have the needed folders on your disk?"

Description

Language: C. Binary only. "Do you have the needed folders on your disk?"

ELF 64-bit, statically linked, stripped.

Analysis

The program checks for the existence of specific directories on the disk. If they exist, it outputs the flag. Using strings and disassembly, we find the directory paths and the verification logic.

Solution

Analysis of strings and binary logic. The flag is constructed from parts when all directory existence checks pass. ‍​‌‌​​‌​​​‌‌​​‌​​​​‌‌​‌​​​​‌‌‌​​‌​​‌‌​​​‌​​‌‌‌​​​​​‌‌​‌‌​​​‌‌​​​​‍

Key Takeaways / Lessons

• Mastering filesystem_check_analysis, string_extraction was key to this challenge.
• Always check for common misconfigurations and verify assumptions.

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Crafted by XESXOR Research • 2026-03-09 • CUSTOM • MC 4 (Dynamic Analysis) • Difficulty: Easy