MC 5 (Dynamic Analysis)

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

Summary

Walkthrough of the CUSTOM Reversing MC 5 (Dynamic Analysis). Language: C. Binary only. "Guess the number again. Flag is the correct one."

Description

Language: C. Binary only. "Guess the number again. Flag is the correct one."

ELF 64-bit, dynamically linked, stripped.

Analysis

The program compares input with a hardcoded number. Through disassembly we find the comparison constant.

Solution

Disassemble the binary, find the cmp instruction with constant REDACTED. ‍​‌‌​​‌​​​‌‌​​‌​​​​‌‌​‌​​​​‌‌‌​​‌​​‌‌​​​‌​​‌‌‌​​​​​‌‌​‌‌​​​‌‌​​​​‍

Key Takeaways / Lessons

• Mastering constant_extraction, disassembly_analysis 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 5 (Dynamic Analysis) • Difficulty: Easy