Frolic — HTB WriteUp

Michael Ikua
5 min readMar 23, 2019


This box was really CTF-like when getting user, it was so unrealistic. You’ll see what I mean. Unfortunately I didn’t get root, not because it was difficult but because I didn’t try.

Getting User

As usual I begin with an nmap scan to get open ports:

nmap -sV -sC -v -oN frolic.txt

I’ll go for the webserver first.

Loading the IP with the port specified we just have a welcome page but at the bottom there’s a link: http://forlic.htb:1880.

Since nmap didn’t pick up that port it means there’s probably some routing based on the host we request. Updating the hosts file and visiting the page once more. There’s a node-red page.

Unfortunately this was a major rabbit hole, so I went back to the previous page and run dirsearch to discover directories. -u -e html,txt,php -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt -t 50 -x 403

Checking the directories only admin and backup had interesting information:

I tried these credentials to login to the admin page but they didn’t work. On checking the source of the admin page there is a login.js that contained the username and password.

username: admin
password: superduperlooperpassword_lol

After logging in I get this:

Now the CTF begins, if you’ve done ctfs before you’ll guess it’s some sort of an esoteric language. But which one? After some researching I narrowed it down to ook! .

Decoding it on this page we get a new directory to check:

Visiting it there’s a page with what looks like base64:

When I encounter such encoding I use CyberChef in case it decodes to a file:

It shows it’s a zip file, I’ll use the terminal to retreive it:

Trying to unzip it asks for a password:

I tried the password that was in the password.txt above but no dice, so I bruteforced it:

fcrackzip -u -D -p /usr/share/wordlists/rockyou.txt

After unzipping there is an index.php file

index.php contents:

Some more encoding!!

The encoding is hex, so I’ll just use xxd:

Another Base64 encoding, decoding that results in another esoteric language called brainfuck:

It decodes to:

Well that doesn’t seem to help move forward, I then realized maybe I may have missed a directory and decided to do a recovery again but this time recursively. I used recursive-gobuster tool:

There are new directories under dev that I hadn’t checked out. Under backup there’s a new directory.

idkwhatispass must be the password after all that decoding we did to find it.

Using admin as user it works.

Exploitation to shell:

Using searchsploit to discover exploits:

There are several exploit for this service, there’s even a metasploit module but I’ll do this manually. I used this to achieve RCE.

This exploit abuses the import feature on the phonebook that uploads a csv file with php.

Here’s the exploit.csv that I will upload:

The strategy is to upload the csv and capture the request with burp then change the user-agent to our reverse shell command and submit.

Browse for csv and import:

Capture request and add reverse-shell command:

Getting shell:

Finally reading user.txt:

Looking around the home folder I find a .binary folder with a file named rop that has a suid bit set. Possibly the privesc route, considering the name I assume its a rop exploit.

Since I didn’t follow through with this I will be waiting for other writeups to see how it was done.


This box had so many rabbit holes and hoops to jump over just to get in. Obviously doesn’t represent any real life scenarios but was fun for CTF lovers like me.

Any questions and feedback is appreciated.

hackthebox: ikuamike

Twitter: ikuamike

Github: ikuamike