Mic Check Four

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

Summary

Walkthrough of the CUSTOM Reversing Mic Check Four. Language: C. Source code provided. Flag checker with length/ASCII and string prefix/suffix checks.

Description

Language: C. Source code provided. Flag checker with length/ASCII and string prefix/suffix checks.

Analysis

Constraints:

1. strlen(input) * 4 == get_char_code_at_position(input, 1) — length × 4 = ASCII of first character
2. strncmp(input, "4_points", 8) — starts with "4_points"
3. strcmp(&input[8], "komne") == 0 — after the 8th character comes "komne"

Solution

• String = "4_points" + "komne" = "REDACTED"
• Length = 13, 13 × 4 = 52 = ASCII('4') ✓ ‍​‌‌​​‌​​​‌‌​​‌​​​​‌‌​‌​​​​‌‌‌​​‌​​‌‌​​​‌​​‌‌‌​​​​​‌‌​‌‌​​​‌‌​​​​‍

Key Takeaways / Lessons

• Mastering ascii_value_calculation, source_code_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 • Mic Check Four • Difficulty: Easy