POST /api/cart/items with JSON body: "productId": 123, "quantity": 1 . Respond with 201 Created .
| Issue | Mitigation | |-------|-------------| | | Cast to int: (int)$_POST['num'] | | Negative quantity | Set default max(1, $num) | | Extremely large num | Apply upper cap (e.g., 999) | | No product ID | Reject request | | CSRF | Use CSRF token in form | | Session fixation | Regenerate session ID after login | | SQL Injection | Use prepared statements for DB cart |
Even if the script correctly validates the num parameter, an attacker can still cause problems by sending repeated requests with large quantities, effectively to legitimate customers.
Historically, developers built shopping carts using unstructured, procedural code that directly modified raw arrays. Modern engineering requires data encapsulation, input sanitation, and safe data types. add-cart.php num
The newline characters ( \r\n ) inject log entries, corrupting log files, evading intrusion detection systems, or filling disk space (log injection DoS).
// 2. Reject obviously invalid input if (!$productId || $productId <= 0 || !$quantity || $quantity <= 0) die('Invalid product ID or quantity.');
// Dummy stock check (in production, query DB) $available_stock = 50; if ($quantity > $available_stock) $quantity = $available_stock; Always escape output using htmlspecialchars() :
Elias stood up, his chair screeching against the linoleum. He walked to the server room, the air growing colder with every step. Through the glass, the status lights of the main frame flickered in a rhythmic, almost pulsing amber.
header('Content-Type: application/json'); echo json_encode(['success' => true, 'message' => 'Product added', 'cart_count' => array_sum(array_column($_SESSION['cart'], 'quantity'))]);
PHP’s loose comparison can cause chaos. If the developer uses if ($num == 1) instead of if ($num === 1) , an attacker could pass num=1abc or num="1" with special characters to bypass checks. When analyzing web traffic logs
When analyzing web traffic logs, security audits, or search queries, the phrase frequently appears. This specific query highlights a common structural pattern—and a critical security risk—in web development: passing product identification numbers directly through URL parameters without proper validation. What is add-cart.php?num= ?
Always escape output using htmlspecialchars() :