Writeup for the retired HTB machine Swag Shop
Link: hhttps://www.hackthebox.eu/home/machines/profile/188
IP: 10.10.10.140

Recon

A qick portscan reveals multiple open ports:

22/tcp    open     ssh     OpenSSH 7.2p2 Ubuntu 4ubuntu2.8 (Ubuntu Linux; protocol 2.0)
80/tcp    open     http    Apache httpd 2.4.18 ((Ubuntu))
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache/2.4.18 (Ubuntu)
|_http-title: Home page

As a website is involved, investigation into interesting files is conducted with gobuster.

gobuster

By investigating the dirs a bit, one can find /app/etc/local.xml, which holds credentials: root:fMVWh7bDHpgZkyfqQXreTjU9
as well as a crypt key:
b355a9e0cd018d3f7f03607141518419 The DB name is swagshop.

As we don’t have any credentials that yield a successful login, we switch to running an exploit to generate them. 37977.py works after a quick code cleanup and setting the target to $IP/index.php.
The admin interface is located at /index.php/admin.
Thanks to the exploit we end up with an admin login forme:forme.

Admin interface & shell

The next step after login is opening a reverse shell.
Most of this is based on the Froghopper attack, which is explained in detail in the liked article.
Prepare a php reverse shell (shell.php) with your IP and Port and change the extension to .jpg to pass the upload filter.
That can be uploaded as the image for a new Category (Catalog -> Manage Categories -> Add Category).
If everything worked well, the file will show up under /media/catalog/category/. Now, to execute the shell, it has to be called. To do that, symlinks need to be activated in System - Configuration - Developer - Template Settings.
Then a new Newsletter Template has to be created with the following content:
``
Afterwards, a click on “preview” will force the server to render the php shell. After the shell connects to the local netcat listener, the user flag can be printed.

Road to root

Enumerating common privilege escalation paths, a sudo entry reveals a possible path:

User www-data may run the following commands on swagshop:
    (root) NOPASSWD: /usr/bin/vi /var/www/html/*

As one can spawn shells within vi, this can be exploited to spawn an elevated shell. So it’s a matter of running sudo vi /var/www/html/LICENSE.txt and then :!bash.