HackTheBox Writeup — Time

Hello Guys , I am Faisal Husaini. My username on HTB is “fa1sal” . Also join me on discord.

The IP of this box is 10.10.10.214

Running NMAP full port scan on it , we get

We see two open ports , both of them for SSH and Web respectively

Moving towards the Web as always

Checking the web, we have a webpage having Online JSON Beautifier and Validator

The Beautify option does the betterment of the JSON code, nothing much to test here

Checking the Validate option, we see that it is on Beta version and when testing some JSON code, we get an error and also it shows the library being used in this application ,i.e, com.fasterxml.jackson.databind

After google searches, we see that this functionality is vulnerable and has an active CVE ,i.e, CVE-2019–12384

We are gonna use the exploit and first try to get the ping back to our machine and below you can see what payload , and the file which is helping us to get the ping back

Our ping back was successful, so now we move towards modifying the payload to get reverse shell

We got the shell as user pericles and also we have the user flag as well

Running PSPY, we see that every 30 seconds there is a user created script running which has the privileges to do the stuffs as root as we can see that it is moving the backups to the root folder

Checking the script contents, we can confirm that its running the zipping and moving the backup file to the root folder and checking the file permissions of the script file, we can see it is owned by user pericles and also we can edit the script as well

We just use the echo command to put our ssh keys into the ssh folder of the root user

Hacker | Bug Hunter | Python Coder | Gamer | Reverse Engineering Lover