# Darkwebmessageboard ![dark](img/dark.png)## Category:### OSINT , Crypto , WebThat's a lot of categories boy.
## Difficulty:### It was pretty difficult
## Writeup:### DISCLAIMER : This is going to be super LONG.....This chall looked interesting because of its three different categories. So I completed the three parts one by one.### First Phase: OSINTThe url http://darkboard-01.pwn.beer:5001 gave a page![dark2](./img/dark2.png)a cool one with a password form. So I viewed the source and found the string :> | Dark Web Message Board | DEVELOPED BY K1tsCr3w | Open source at Kits-AB 
which was commented out. Open Source gave a hint to github. So I searched in github for the user Kits-AB and got the source for the website. https://github.com/kits-ab/the-dark-message-board. Checking the directories, **robots.txt** caught my eye. It had an entry __/boards/*__. Opening http://darkboard-01.pwn.beer:5001/boards/1 gave a message board which contained lot of messages. The one which was of importance was :```rW+fOddzrtdP7ufLj9KTQa9W8T9JhEj7a2AITFA4a2UbeEAtV/ocxB/t4ikLCMsThUXXWz+UFnyXzgLgD9RM+2toOvWRiJPBM2ASjobT+bLLi31F2M3jPfqYK1L9NCSMcmpVGs+OZZhzJmTbfHLdUcDzDwdZcjKcGbwEGlL6Z7+CbHD7RvoJk7Ft3wvFZ7PWIUHPneVAsAglOalJQCyWKtkksy9oUdDfCL9yvLDV4H4HoXGfQwUbLJL4Qx4hXHh3fHDoplTqYdkhi/5E4l6HO0Qh/jmkNLuwUyhcZVnFMet1vK07ePAuu7kkMe6iZ8FNtmluFlLnrlQXrE74Z2vHbQ==```It was encrypted with something. Getting back to git repo, the tests dir had a test_crypto.py (this file was of super importance). Since it was OSINT the repo had 3 commits. So I looked the commit history which had this fishy commit which was deleted.![dark3](./img/dark3.png) So i viewed it and it had a __PRIVATE_KEY__ (which was to be used later) and a description: ``` removed the production key, luckily it was encrypted with a password …
…from some file that reminds me of the song 'here i am something like a hurricane'```The song in the description was __Rock_You_Like_a_Hurricane__ , so with this I concluded that somehow rockyou.txt was involved in the chall. And this ends our OSINT phase.
### Second Phase: CryptoNow comes the file __test_crypto.py__. Understanding the file, the script carries out random generation of private keys on top of a password and a PADDING... (Boy oh Boy that much Security).So this was the script in a nutshell, with this we needed to find a password from rockyou.txt to decrypt the text obtained from __/boards/1__ . So i modified the test_crypto.py to accomplish this. Here's my modified decryption function.```pythonwith open("rockyou.txt", errors='replace') as f:    r = f.readlines()    p_list = [i.strip() for i in r]for l in p_list:    try:        private_key =              serialization.load_pem_private_key(                    PEM_PRIVATE_KEY,                    password=bytes(l, 'utf-8'),                    backend=default_backend() )         plaintext = private_key.decrypt(    base64.b64decode(ENCRYPTED_MESSAGE.encode('utf-8')),DEFAULT_PADDING)        print(plaintext)    except:        continue```I looped thorugh all the pwds from rockyou to get a hitand replaced the PRIVATE_KEY with the one given in github deleted commit and waited for the decrypted text to appear. The heavy load nearly crashed my box. The decrypted text was a URL for our next phase.>Bank url: http://bankofsweden-01.pwn.beer
This marked the end for our Crypto Phase.
### Third Phase: Web Now the last and the longest phase. Opening the URL obtained got me nowhere. So the chall desription had this :```You will find a URL. If it says https://XXXXXXXXX/, change it to http://XXXXXXXXX:5000/```So our modified URL changed to http://bankofsweden-01.pwn.beer:5000 
It directed us to the BANK website which the chall had in its description. It had a Login and Registration form. I registered with some creds but for some reason the account did'nt seem to activate. So while registering, I captured the request with Burp-Suite.It had an __is_active__ param. Setting it to true did the trick to activate our account.![dark4](./img/dark4.png)Logging in gave us a Greeting msg (Nice site)![dark5](./img/dark5.png)Exploring the site, it had two features IMPORT and EXPORT. I first used the export feature![dark6](./img/dark6.png)When I clicked the export btn It tried to open a file which wasn't present in the dir. So It was a bit suspicious. So I called my frnd BURP again and captured the req. The param account had LFI so I used it to my advantage.![dark7](./img/dark7.png)Hahah I got /etc/passwd. Now the real part came. looking for the flag..... It took some time to find the dir and the flag file. Using __/proc/self/environ__I looked through the env variables and found this:>PWD=/home/bos/ctf
This was the last lead which I found and it took me a while to figure out that the webapp was FLASKED...(based on flask).So I looked tried tha app.py inside ctf/>/home/bos/ctf/app.py![dark8](./img/dark8.png)
and yeaaa....It worked and the flag was right there.```sctf{h4ck3r5_60nn4_h4ck_4nd_b4nk3r5_60nn4_cr4ck}```That was the longest chall I ever solved.Hats off the my team mates:[nullpxl](https://github.com/nullpxl)[mrT4ntr4](https://github.com/mrT4ntr4) for helping me with this chall.
Hope u like it.Team [Dc1ph3R](https://ctftime.org/team/69272).
The full script to the crypto part: [darkcrypto.py](https://github.com/Himanshukr000/Security-Fest-2019/blob/master/darkcrypto.py)