HackTheBox Ransom Challenge
Explore the basics of cybersecurity in the Ransom Challenge on Hack The Box. This easy-level Challenge introduces encryption reversal and file handling concepts in a clear and accessible way, perfect for beginners.
https://app.hackthebox.com/challenges/166
Description
We received an email from Microsoft Support recommending that we apply a critical patch to our Windows servers. A system administrator downloaded the attachment from the email and ran it, and now all our company data is encrypted. Can you help us decrypt our files?
Exploitation
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#!/usr/bin/env python3
def decrypt_file(encrypted_file_path, output_file_path):
KEY = "SUPERSECURE"
key_length = len(KEY)
try:
with open(encrypted_file_path, 'rb') as f:
encrypted_data = f.read()
decrypted_data = bytearray()
for i in range(len(encrypted_data)):
decrypted_byte = encrypted_data[i] - ord(KEY[i % key_length])
decrypted_data.append(decrypted_byte & 0xFF)
with open(output_file_path, 'wb') as f:
f.write(decrypted_data)
print(f"Successfully decrypted {encrypted_file_path} to {output_file_path}")
except Exception as e:
print(f"Error during decryption: {str(e)}")
if __name__ == "__main__":
decrypt_file('login.xlsx.enc', 'out.zip')
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python poc
unzip out.zip
rg "HTB"
Summary
The Ransom Challenge on Hack The Box is an easy-level reverse engineering puzzle that introduces basic file decryption techniques. Participants decrypt a file encrypted with a simple XOR-like algorithm using a fixed key (SUPERSECURE), then extract the hidden flag from the recovered data. Ideal for beginners, it provides hands-on experience with encryption reversal and file manipulation, offering a practical introduction to basic cryptographic concepts.