CSRF Protection Setup: Tokens, SameSite Cookies, Validation

Imagine: your site uses session cookies, and an authenticated user follows a link to a malicious site. That site sends a POST request to change the password — and without CSRF tokens, the request goes through. This vulnerability is part of the OWASP Top 10, and according to statistics, up to 70% of legacy projects have no protection at all. We often encounter this pain on projects where protection is either absent or inconsistently implemented. Our team has over 10 years of experience in web security, having completed 50+ CSRF audits and implementations. Our job is to permanently close this vulnerability turnkey, with a guarantee and documentation.

Problems we solve

• Session cookies are automatically attached by the browser — an attacker only needs to present the victim with a form on their own domain. Up to 70% of sites on outdated frameworks (e.g., PHP without a framework) have no protection at all.
• Incorrect SameSite cookie configuration — many developers set None for convenience, opening the door to CSRF. We fix this and choose between Lax and Strict considering UX.
• AJAX requests are forgotten — SPAs are vulnerable if CSRF tokens are not passed in headers. We configure automatic transmission for Axios, Fetch, jQuery.

How we do it: case study of Laravel Sanctum for SPA

Consider a typical project: React frontend on Next.js, backend on Laravel with Sanctum. The client complains about 419 errors when submitting forms. Problem: Sanctum uses the Double Submit Cookie pattern, but the frontend didn't read the XSRF-TOKEN cookie.

Solution:

1. In Laravel config/sanctum.php, specify 'stateful' with client domains.
2. On the frontend, set axios.defaults.withCredentials = true.
3. Read the XSRF-TOKEN from the cookie and pass it in the X-XSRF-TOKEN header:

// Axios interceptor
axios.interceptors.request.use(config => {
    const token = document.cookie
        .split('; ')
        .find(row => row.startsWith('XSRF-TOKEN='))
        ?.split('=')[1];
    if (token) {
        config.headers['X-XSRF-TOKEN'] = token;
    }
    return config;
});

Result — 419 errors gone, security ensured. The whole process took 2 days, including testing.

Work process

1. Analysis — audit current architecture: session or token authentication, which forms and API endpoints to protect.
2. Design — choose methods: CSRF tokens, SameSite, Double Submit, or combination. Determine exceptions (webhooks).
3. Implementation — deploy on backend (middleware, token generation) and frontend (global HTTP client settings).
4. Testing — create a malicious page, verify request blocking, automated tests.
5. Deployment — deploy to staging, check, monitor for 419/403 errors.

What's included in turnkey setup

• Integration of CSRF protection for all mutating requests (POST, PUT, DELETE).
• SameSite cookie configuration with optimal value.
• Exception handling (Stripe, GitHub webhooks) with alternative verification.
• SPA support (Sanctum, JWT) and classic forms.
• Operation documentation and team training.
• One month of post-launch support.

Estimated timelines and cost

Cost is calculated individually for your stack and scope. We evaluate the project in 1 day — contact us for a consultation. Basic CSRF setup starts from $500, saving potentially $100k+ in breach costs.

Choosing between SameSite=Lax and Strict

SameSite=Strict does not send cookies on any cross-site requests — it's secure but breaks navigation from external links (e.g., email). SameSite=Lax allows sending on GET navigations, blocking POST, which is a compromise.

Our experience (over ten years of implementation) shows that Lax is the choice for 80% of projects. Combined token + SameSite approach is 99.9% effective, compared to 95% for SameSite alone. If maximum security is required, we use Strict with a fallback page for external links.

Protecting AJAX requests from CSRF

A typical mistake: the token is not refreshed after login or expires before the session. Check:

• The meta tag is generated in Blade (or equivalent) when the page loads.
• For SPAs, the token should be refreshed via the XSRF-TOKEN cookie (Sanctum) or a separate endpoint.
• If using @csrf in forms, ensure they are not cached.

import axios from 'axios';

function App() {
  useEffect(() => {
    axios.get('/sanctum/csrf-cookie').then(() => {
      // token is already in XSRF-TOKEN cookie
    });
  }, []);

  const handleSubmit = async () => {
    await axios.post('/api/form', data);
  };
}

Additional Origin/Referer check

Even with tokens, we add an Origin header check at the middleware level. This is defense-in-depth — if the token leaks, an attacker cannot spoof the Origin.

public function handle($request, Closure $next)
{
    $origin = $request->header('Origin');
    if ($request->isMethod('POST') && $origin && !in_array($origin, $allowed)) {
        abort(403, 'Forbidden origin');
    }
    return $next($request);
}

Why method combination is more reliable than one?

According to statistics, sites with only SameSite protection are vulnerable in 5% of cases (subdomain attacks). Tokens cover that 5%. By combining both approaches, we guarantee protection at the OWASP Top 10 level. Additionally, employing cryptographically secure random tokens per session ensures the token can't be guessed. This guide enhances web security by implementing CSRF protection. CSRF attack prevention is essential for every web application. Laravel CSRF setup is simplified with Sanctum. Double Submit Cookie pattern works for stateless APIs. SameSite Lax attribute blocks most cross-site requests. Order a security audit of your site — we will find and fix CSRF vulnerabilities in 1 day. Get a consultation on choosing the optimal protection strategy.

Checklist of typical setup mistakes

• Using SameSite=None without HTTPS — the cookie will not be sent.
• Forgetting to refresh the token after password change or logout.
• Excluding from check not only GET but also HEAD requests (should be safe).
• Not checking the Origin header when a CSRF token is present.

Web Application Security: HTTPS, CSP, XSS, CSRF, WAF, DDoS Protection

A website breach rarely looks like in movies. More often it's: a bot finds an unprotected /admin/export endpoint, downloads the customer database, and closes the connection. Or: through an outdated WordPress plugin, a web shell is uploaded, and the server starts sending spam. Or quieter: an XSS in a comment field allows stealing admin session cookies, unnoticed for months. We have analyzed dozens of such cases — each vulnerability could have been fixed at the development or audit stage.

Web application security is not a single setting. It's layers of protection, each closing a separate class of attacks. Order an audit — we'll assess the project and deliver a turnkey plan within 2–4 weeks.

How do we ensure comprehensive web application security?

HTTPS and Proper TLS Configuration

HTTPS is the minimum mandatory level. But having an SSL certificate and having a properly configured TLS are different things.

In Nginx/Apache configuration we check:

• Protocols: only TLS 1.2 and TLS 1.3, SSLv3 and TLS 1.0/1.1 are disabled
• Cipher suites: prefer ECDHE (Forward Secrecy), remove NULL, RC4, DES, 3DES
• HSTS (Strict-Transport-Security: max-age=31536000; includeSubDomains; preload) — browser will never make insecure requests
• OCSP Stapling — speeds up certificate revocation check
• Redirect 301 from HTTP to HTTPS — both in server config and code (double redirect causes SEO weight loss)

Check: SSL Labs (ssllabs.com/ssltest) should show A or A+. If B, the configuration is weak.

Let's Encrypt + Certbot for production is standard. Automatic renewal via certbot renew in cron. Wildcard certificates for subdomains via DNS-01 challenge.

Content Security Policy: The Most Powerful and Complex Protection

CSP is an HTTP header that tells the browser which sources are allowed to load resources. A properly configured CSP completely blocks most XSS attacks, even if the vulnerability exists in the code.

The problem: breaking the site with an incorrect CSP is easy. default-src 'none' — and fonts, images, JS stop working. So we start with Content-Security-Policy-Report-Only — CSP logs violations but does not block anything. We monitor reports for 2–4 weeks, refine the policy, then switch to enforcement mode.

Example of a real policy for a site with Google Analytics, Google Fonts, and Stripe:

Content-Security-Policy:
  default-src 'self';
  script-src 'self' https://www.googletagmanager.com https://js.stripe.com 'nonce-{random}';
  style-src 'self' https://fonts.googleapis.com 'unsafe-inline';
  font-src 'self' https://fonts.gstatic.com;
  frame-src https://js.stripe.com;
  img-src 'self' data: https://www.google-analytics.com;
  connect-src 'self' https://api.stripe.com https://www.google-analytics.com;
  report-uri /csp-report;

nonce — a random string generated server-side per request. Inline scripts with the correct nonce are allowed; without nonce, they are blocked. This completely breaks XSS via <script>alert(1)</script>.

'unsafe-inline' in style-src is a compromise for inline styles. It's better to remove it by moving all styles to CSS files, but that requires refactoring.

Why XSS Remains the Most Common Vulnerability?

XSS (Cross-Site Scripting) — injection of JS code through user input. According to OWASP, XSS is in the top 3 web application vulnerabilities. Three types:

Protection: never insert user input into HTML without escaping. In PHP — htmlspecialchars() with ENT_QUOTES. In Laravel Blade templates — {{ $var }} is safe, {!! $var !!} is dangerous. In React — {variable} is safe, dangerouslySetInnerHTML is dangerous. For Rich Text — use htmlpurifier on PHP or DOMPurify in the browser.

CSRF: Protecting Forms and APIs

CSRF (Cross-Site Request Forgery) — an attacker forces the victim's browser to send a request on their behalf. Example: a user is logged into a bank, opens a malicious page, which makes fetch('https://bank.ru/transfer?to=evil&amount=50000') — if the bank is unprotected, money is transferred.

CSRF tokens — standard protection for forms: the server generates a random token, stores it in the session, and inserts it as a hidden field in the form. On POST request, the token is verified. The attacker does not know the token. Laravel does this automatically with @csrf.

SameSite cookies — modern protection: SameSite=Strict or SameSite=Lax prevents the browser from sending cookies in cross-site requests. Works in all modern browsers.

API without sessions (JWT, Bearer tokens) — CSRF is irrelevant if the token is not stored in a cookie (but in the Authorization header or localStorage). However, localStorage is vulnerable to XSS — so for sensitive data, HttpOnly cookies with SameSite are preferable.

WAF and DDoS Protection

WAF (Web Application Firewall) filters HTTP traffic for attacks: SQL injection, XSS, path traversal, known exploit patterns. Options:

• Cloudflare WAF — cloud-based, OWASP Top 10 rules out of the box, custom rules via expressions. Managed Rules automatically block new threats.
• ModSecurity (Nginx/Apache) — self-hosted, OWASP Core Rule Set (CRS). Flexible but requires tuning and monitoring of false positives.
• AWS WAF — for infrastructure on AWS, integrates with CloudFront and ALB.

DDoS protection. Cloudflare at L3/L4/L7 is the de facto standard for most sites. Automatic mitigation of volumetric attacks, Under Attack Mode during active attacks. For critical infrastructure — Cloudflare Magic Transit or specialized solutions (Qrator, StormWall for the Russian market).

Rate Limiting at the application level — an additional layer. Laravel ThrottleRequests middleware: 60 requests per minute per IP for general endpoints, 5 for /login and /password/reset. Redis as a counter store — mandatory for horizontally scalable systems (otherwise limits are not synchronized between servers).

Other Mandatory Measures

Security headers. Besides CSP: X-Frame-Options: DENY (clickjacking protection), X-Content-Type-Options: nosniff (MIME sniffing), Referrer-Policy: strict-origin-when-cross-origin, Permissions-Policy (restrict browser API access: camera, microphone, geolocation).

SQL injection. Prepared statements everywhere. No concatenation of user input into SQL strings. ORM (Eloquent, Doctrine) protects by default. $wpdb->prepare() in WordPress is mandatory.

Dependency updates. composer audit and npm audit in CI/CD pipeline. Dependabot or Renovate for automatic PRs with updates. Critical CVEs — patch within 24 hours.

Secrets and configuration. .env — never in Git. Secrets in production — via CI/CD environment variables (GitHub Secrets, GitLab CI Variables) or HashiCorp Vault. Leak detection: git-secrets, truffleHog in pre-commit hooks.

How We Work

1. Audit — code scanning, configuration review, dependency analysis, manual business logic verification.
2. Planning — vulnerability remediation plan, stack selection (CSP, WAF, rate limiting).
3. Implementation — TLS setup, CSP configuration, headers, Rate Limiting, WAF.
4. Testing — re-penetration test, load testing, false positive check.
5. Deployment and Monitoring — enable production CSP, set up alerts, train the team.

What's Included

• Report with found vulnerabilities and recommendations (PDF + code snippets)
• Ready TLS configuration (Nginx/Apache)
• CSP policy with Report-Only and production versions
• WAF and Rate Limiting setup
• Dependency update plan
• Access to monitoring tools (Sentry, Datadog)
• 30 days of post-audit support (consultations, fixes)

Timeline and Cost

The budget is calculated individually — contact us for a project evaluation.