Add-cart.php Num Online

In the world of e-commerce development, few scripts are as ubiquitous—and as notoriously vulnerable—as add-cart.php . At first glance, it seems harmless: a simple backend handler that adds a product to a user’s shopping cart. But when you see a URL like https://example.com/add-cart.php?num=1 , alarms should go off for any experienced developer.

The attacker uses Burp Suite to fuzz the num parameter with a payload list: 1 , 1.1 , -1 , 999999 , 1 UNION SELECT 1 , 1%00 .

If you currently have add-cart.php?num= in production, stop reading and go audit it now. Your users’ data—and your business—depend on it. add-cart.php num

Never trust user input. Always validate data types. Never use GET requests to modify state. And for the love of security, move away from raw add-cart.php scripts and toward modern, token-authenticated POST endpoints.

// In the form that calls add-cart $_SESSION['csrf_token'] = bin2hex(random_bytes(32)); echo '<input type="hidden" name="csrf_token" value="'.$_SESSION['csrf_token'].'">'; // In add-cart.php if (!hash_equals($_SESSION['csrf_token'], $_POST['csrf_token'])) die('CSRF attack detected'); In the world of e-commerce development, few scripts

$stmt = $conn->prepare("SELECT price, stock FROM products WHERE id = ? AND active = 1"); $stmt->bind_param("i", $product_id); $stmt->execute(); Principle 4: Implement CSRF Tokens Since you are modifying state (the cart), every request must include a unique token.

if (isset($_SESSION['last_cart_action']) && (time() - $_SESSION['last_cart_action']) < 0.5) header('HTTP/1.1 429 Too Many Requests'); exit; The attacker uses Burp Suite to fuzz the

The attacker crafts add-cart.php?num=12 AND 1=2 UNION SELECT database()-- - . The cart page inadvertently displays the database name (e.g., "vintage_store_db") because the product name lookup fails and falls back to the error message.