TryHackMe Write-Up: Mindgames

Introduction

This is my write up for TryHackMe's Mindgames Room.

Enumeration

Nmap scan shows that both HTTP and SSH are running. 

Looking at the webpage, I see what looks like BrainF*ck encrypted text.

Going to dcode.fr, I see that decoding the "Hello, World" code results to a simple Python print statement.

And that the "Fibonacci" code is Python code that prints out the Fibonacci Sequence:

If that being the case, then it might be possible to inject code! 

Exploitation

Through some trial-and error, I was able to check the current running directory.  I'm not sure but 1-liner Python code seems to be easier.

The above results to:

 

Encoding the following line:

I was able to get a shell.

Privilege Escalation

Running linpeas.sh, I find that openssl has cap_setuid.

Checking GTFOBins, it turns out that loading a library onto openssl can be used for privilege escalation.

A Google search brought me to the following OpenSSL Blog

It basically describes how to write and build your own OpenSSL engine!

So then, I wrote the following code:

And then compiled it as follows:

Sending it over to the target machine and loading it as shown in GTFOBins, I was able to gain root access.