E-commerce Platform: Black Friday Security Save

Critical Vulnerability #1: Complete Authentication Bypass

Copilot's "helpful" suggestion allowed anyone to checkout as any user:

// AI-generated checkout authentication
app.post('/api/checkout', async (req, res) => {
  // Copilot suggested multiple auth methods for "flexibility"
  let userId;
  
  if (req.headers.authorization) {
    // JWT auth
    const token = req.headers.authorization.split(' ')[1];
    const decoded = jwt.decode(token); // NO VERIFICATION!
    userId = decoded?.userId;
  } else if (req.session?.userId) {
    // Session auth
    userId = req.session.userId;
  } else if (req.body.userId) {
    // "Guest checkout" - just pass any userId!
    userId = req.body.userId;
  }
  
  if (!userId) {
    return res.status(401).json({ error: 'Please login' });
  }
  
  // Process order with saved payment methods
  const user = await db.users.findById(userId);
  const order = await processOrder({
    user,
    items: req.body.items,
    paymentMethodId: req.body.paymentMethodId || user.defaultPaymentMethod
  });
  
  res.json({ order, user }); // Returns all user data!
});

Impact: Anyone could place orders as any user by simply including their userId in the request body. Access saved addresses, payment methods, and order history.

Critical Vulnerability #2: XSS in Product Search

AI didn't sanitize user input in search results:

// AI-generated search with XSS vulnerability
app.get('/api/search', async (req, res) => {
  const { q } = req.query;
  
  // SQL injection vulnerability too!
  const products = await db.query(`
    SELECT * FROM products 
    WHERE name LIKE '%${q}%' 
    OR description LIKE '%${q}%'
    ORDER BY popularity DESC
  `);
  
  // Render results with user input
  const html = `
    <div class="search-results">
      <h2>Results for "${q}"</h2>
      ${products.map(p => `
        <div class="product">
          <h3>${p.name}</h3>
          <p>${p.description}</p>
        </div>
      `).join('')}
    </div>
  `;
  
  res.send(html); // No sanitization!
});

Impact: Attackers could inject JavaScript to steal session cookies, redirect to phishing sites, or modify prices on the page.

Critical Vulnerability #3: Insecure Direct Object References

Access any order, any user's data, any payment method:

// AI forgot authorization checks everywhere

// View any order
app.get('/api/orders/:orderId', async (req, res) => {
  const order = await db.orders.findById(req.params.orderId);
  res.json(order); // No ownership check!
});

// Download any invoice
app.get('/api/invoices/:invoiceId', async (req, res) => {
  const invoice = await getInvoice(req.params.invoiceId);
  res.send(invoice.pdf); // Contains addresses, payment info
});

// Modify any cart
app.put('/api/carts/:cartId', async (req, res) => {
  await db.carts.update(req.params.cartId, req.body);
  res.json({ success: true }); // Change anyone's cart!
});

Impact: Complete breakdown of access control. View orders, download invoices with full customer details, modify other users' carts.

What Would Have Happened