Hack the Fortress VM (CTF Challenge)

Hello friends today we are going to solve another CTF challenge “FORTRESS” of the vulnhub labs. The level of this challenge is not so tough and its difficulty level is described as medium. Solving this lab will give you a good experience of web penetration testing.

You can download it from here: https://www.vulnhub.com/entry/dc416-2016,168/

Penetrating Methodology

§  Network Scanning (Nmap, netdiscover)

§  Abusing HTTP service (Burp-suite)

§  Generating Dictionary (crunch)

§  Cracking Hash (john the ripper)

§  SSH login

§  Capture the 2^nd flag and 3^rd flag

                                                                         

Let’s Begin!!

Start with netdiscover command to identify target IP in the local network, in my network 192.168.1.109 is my target IP, you will get yours.

netdiscover

Further let’s enumerate open ports and protocols information of the target’s network with help of nmap following command:

nmap -p- -A 192.168.0.109

As shown port 22, 80, 443 are open, let’s penetrate more.

     So we explore target IP in the web browser and welcomed by following image.

After making lots of efforts I decided to use dirbuster for directory brute-force. Type dirbuster on terminal and automatically OWASP dirbuster window gets open. Here browse your dictionary from /usr/share/dirbuster/wordlists and choose your appropriate wordlist as I select medium.txt, do not forget to address target URL in top of text field as: http//192.168.0.109 and finally hit start button.

   Luckily!!! I found something which is scanner.php file.

So when I explored scanner.php in the web browser, it put-up the following web page in front of us.  So when I trigger the localhost IP we got result of Nmap scan which you can perceive from below image. I also tried to breach it through some kind of command injection but hard luck! all seems to be waste here.

Then I decide to capture the HTTP request in burp suite and send the intercepted request into repeater. 

Look over given below image here you will find two panel left and right for request and response respectively.

Type ls as request and click on go tab. This will generate response to request you made.

Request: ls

Response: index.html

k1ngd0m_k3yz

logo.png

s1kr3t

scanner.php

styles.css

So among 4 directories enumerated above, we ran ls command again to check the list of /s1kr3t and found flag.txt as response.

Request: ls

Response: flag.txt

Now repeat the process till last step of making request and getting response through repeater. With help of cat command we found 1^st flag.

 Request: cat flag.txt

Response: FLAG{n0_one_br3aches_teh_f0rt}

Then we try to check list of k1ngd0m_k3yz and found two files inside it.

Request: ls k1ngd0m_k3yz

Response: master and passwd

So I open master file and found a single entry of /etc/passwd file for user craven along with password hash.

Request: cat k1ngd0m_k3yz/master

Let’s copy the hash password in a text file and named it hash.txt

Then I open /k1ngd0m_k3yz/passwd where I didn’t found any remarkable clue.

Then I try to open /etc/passwd file and as you can observe, inside burp response we got the passwd file and I found entry for two local users: vulnhub & craven.

Then, I try to get into /home/craven directory in order to view present list with following request.

Request: ls  /home/craven

Response: I got three files flag.txt, hint.txt and reminders.txt.

First I try to flag.txt but fail to read it, then inside hint.txt we got some hint for user password.

 Then I open reminder.txt file that gave me a list to buy.

Then with help of hint.txt and remainder.txt we have generated a dictionary using crunch. Crunch is a wordlist generator where you can specify a standard character set or a character set you specify.

crunch 10 10 -t %%%qwerty^ > dict.txt

If you remember we have already enumerated hash password for craven from inside k1ngd0m_k3yz/master. Use john the ripper to crack the password with help crunch dictionary generated above.

cd Desktop

 john --wordlist=dic.txt hash.txt

 931qwerty? is password for craven as you can perceive from the given image.

If you remember the result from nmap which shows port 22 is open now try to connect the target through SSH using above credential.

ssh craven@192.168.0.109

Yesss!! We got login successfully, now when I checked the list of current directory, I found flag.txt.

ls

cat flag.txt

Luckily found 2^nd FLAG {w0uld_u_lik3_som3_b33r_with_ur_r3d_PiLL}

It was very tough to get third flag.txt but with help of following command we reached to the final flag.

cd /home

ls             

cd vulnhub

ls

cat flag.txt

./reader flag.txt

For finding 3^rd flag we applied the symlink process and successfully grabbed the last flag also.

cd /tmp

ln /home/vulnhub/flag.txt raj

cd /home/vulnhub

./reader /tmp/raj

Finally I found 3^rd FLAG{its_A_ph0t0_ph1ni5h}