Implement anti-CSRF tokens in your web forms. Libraries like csurf for Express can help you generate and validate these tokens. Example using csurf:
const csurf = require('csurf'); const csrfProtection = csurf({ cookie: true });
app.use(csrfProtection);
app.get('/myform', (req, res) => { // Use csrfToken in your form res.render('myform', { csrfToken: req.csrfToken() }); });
Set the SameSite attribute for cookies to mitigate CSRF attacks.
app.use(session({ secret: 'your-secret-key', cookie: { sameSite: 'strict' }, }));
Implement a Content Security Policy to control which resources can be loaded on your page.
app.use((req, res, next) => { res.setHeader('Content-Security-Policy', 'script-src 'self''); next(); });
Sanitize user input and encode it properly before rendering it on the page. Libraries like he can be useful for HTML encoding.
const he = require('he');
const userInput = '<script>alert("XSS attack")</script>'; const encodedInput = he.encode(userInput);
Use the helmet middleware to set various HTTP headers, including XSS protection headers.
const helmet = require('helmet'); app.use(helmet());
If you're using template engines, ensure they automatically escape content by default. For example, in EJS:
<%- userContent %>