Hack the Box (HTB) machines walkthrough series — JSON

Today we will be continuing with our exploration of Hack the Box (HTB) machines, as seen in previous articles. This walkthrough is of an HTB machine named JSON.

HTB is an excellent platform that hosts machines belonging to multiple OSes. It also has some other challenges as well. Individuals have to solve the puzzle (simple enumeration plus pentest) in order to log into the platform and download the VPN pack to connect to the machines hosted on the HTB platform.

Note: Only write-ups of retired HTB machines are allowed. The machine in this article, named JSON, is retired.

The walkthrough

Let’s start with this machine.

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1. Download the VPN pack for the individual user and use the guidelines to log into the HTB VPN.
2. The JSON machine IP is 10.10.10.158.
3. We will adopt the same methodology of performing penetration testing as before. Let’s start with enumeration in order to gain as much information about the machine as possible.
4. As usual, let’s start with the nmap scan to gather more information about the services running on this machine. [CLICK IMAGES TO ENLARGE]
   <<nmap -sC -sV -oA Json 10.10.10.158>>
   
   
5. As we can see, a lot of interesting ports are shown. Let’s begin their enumeration next. Below is the service available on port 80.
   
6. Using the default admin creds gets us in.
   
7. Let’s get the request parsed via Burp. If we look closely, we can see that the bearer field and cookie token are the same.
   
8. And if we decode them, we get the same request parameters.
   
9. For testing, I deleted the bearer field. The response was null.
   
10. I then added the random text “lhm”, Base64-encode it and pass it in the bearer field. We got a deserialization error.
    
11. We can try to exploit JSON deserialization. Here, I (Read more...)