Baby Crypt

Platform: HackTheBox | Category: Reversing | Difficulty: Easy | Author: D3v0o0Nu11 | Date: 2026-02-10

Description

Give me the key and take what's yours.

Solution Approach

Core idea: Identify the weakness from source review or fingerprinting first. Iterate with incremental payloads instead of guessing.

Steps

1. First, unzip the .zip file given.

2. Since we got a binary file, let's decompile it with ghidra.

3. Based from it we know that the key is 4 characters and there's a XOR algorithm.

4. It's a basic XOR concept, since the first 4 characters of the plaintext we want is `REDACTED

5. Now we're given the XOR. Simply enter copy the first 4 characters of the XORed characters as the key -> w0wD.

6. Got the flag!

Flag

REDACTED

Lessons Learned

1. Identify the weakness from source review or fingerprinting first.
2. Iterate with incremental payloads instead of guessing.
3. Reuse the same pattern in future engagements.