crackme2

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

Summary

Walkthrough of the CUSTOM Reversing crackme2. Language: C. Source code provided. Flag is hex-encoded in the source.

Description

Language: C. Source code provided. Flag is hex-encoded in the source.

Analysis

The program converts input to a hex string via sprintf(ptr, "%02x", text[i]) and compares it with a hardcoded string:

 c read-only • copy allowed Copy
const char *flag = "464c41477b32653135356238376435383234653835656634313039346165633761383364637d";

Solution

Simply decode hex to ASCII:

 python read-only • copy allowed Copy
flag_hex = "464c41477b32653135356238376435383234653835656634313039346165633761383364637d"
flag = bytes.fromhex(flag_hex).decode()
# FLAG{REDACTED}

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Key Takeaways / Lessons

• Mastering hex_decode, 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 • crackme2 • Difficulty: Easy