Table of Contents

Solve the HTB Weak RSA Crypto challenge with ease. Based on the RSA cipher, this easy challenge requires the use of an automated RSA attack tool like the RsaCtfTool. Get the flag with a simple command and expand your crypto skills with HackTheBox challenges.

Provided Files:

You are provided with the following files:

  • flag.enc
  • key.pub

Walk-through:

At first glance, you’d think you can decrypt the flag with the public key.
For that, we might use the OpenSSL package to decrypt the flag. This time it’s a bit different and you’ll find that the OpenSSL package won’t work for this challenge.

We’ll use an automated RSA attack tool. A common python script is the RsaCtfTool

python3 RsaCtfTool.py --publickey ./key.pub --uncipherfile ./flag.enc

Simply put, this tool finds the flag easily for you in an automated fashion.

Flag Example: 

HTB{XXXXXX_XXXXXXX_XXXXXX}