PierreRambaud / security_examples

A little PrestaShop module, to explain how to protect against security issues.

PrestaShop Security Module

About

Module to helps you to understand what kinds of security issues exist and how you can prevent it.

Requirements

A working Prestashop 1.7.5 instance and composer (only for development).

PrestaShop Day Presentation

View presentation: https://docs.google.com/presentation/d/1IePuou2D3g1asvGQm1Ni68VLyyaAYJ5Kth7cWOM2cq4/edit?usp=sharing

Understanding exploits

RCE (Remote Code Execution)

Never execute something you can't control. Prefer whitelist as much as possible, or escape string. For example, if you're using Symfony\Component\Process\Process, use the default method to escape commands:

$process = new Process(
    [
        $this->getParameter('kernel.root_dir') . '/../bin/console',
        'debug:' . $type // This one will be automatically escaped
    ]
);
$process->run();

or escapeshellarg

$process = exec(
    __PS_ROOT_DIR__ . '/bin/console ' . 
    escapeshellarg('debug:' . $type)
);

Xss (Cross Site Scripting)

If you don't care about this, you're completly wrong! A thief can take screenshot of your browser, retrieve all form data, control your webcam, get your cookies, ... And if you're using a CMS, with a little piece of code, can create and admin account without being notify. Get a look at (https://beefproject.com/)[https://beefproject.com/], you'll be surprised.

So, don't be shy, always sanitize data and do not display it directly, use htmlentities, htmlspecialchars, ...

SQL Injection

Like others, never trust something you don't control. With a simple script, an attacker can retrieve or create many thing into your database. Or even try to bruteforce your database password.

found_chars = ''
for i in range(20):
    for c in characters:
        try:
            blind_sql = '?username='+username+'" AND IF(password like BINARY "' + found_chars + c + '%",sleep('+sleepTime+'),null)"'
            r = requests.get(target + blind_sql, timeout=5)
        except requests.exceptions.Timeout:
            found_chars += c
            print 'Found chars in password: ' + found_chars
            break

Watch out with rights you give to your database user.

LFI (Local File Include)

Same as previous, use whitelist, identifier to request a file instead of its real name. Prefer http://website.com/download/files/2934 or http://website.com/download/files/my-file than http://website.com/download?file=csv/my-file.csv.