Fix Broken Authentication in Symfony Easily

Broken Authentication is one of the most common and dangerous security vulnerabilities found in modern web applications, including Symfony-based projects. When authentication is not implemented correctly, attackers can exploit it to impersonate users, including admins, and gain unauthorized access to sensitive data.

In this blog post, we’ll explore how Broken Authentication happens in Symfony, how you can detect it using our free website vulnerability scanner online tool, and most importantly, how to fix it with secure coding examples.

👉 Also, check out other latest vulnerabilities at our blog: Pentest Testing Corp.

🔍 What is Broken Authentication?

Broken Authentication occurs when session management or credential mechanisms fail to protect against unauthorized access. Common causes in Symfony applications include:

• Predictable session IDs

• Insecure password storage

• Weak login validation

• No brute force protection

• No multi-factor authentication
  
  

💣 Real-World Example of Broken Authentication in Symfony

Let’s say you’re using the Symfony Security component to handle user authentication. Here’s a minimal login controller example with a critical mistake.

❌ Vulnerable LoginController.php

// src/Controller/LoginController.php

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

use Symfony\Component\HttpFoundation\Request;

use Symfony\Component\Security\Http\Authentication\AuthenticationUtils;

class LoginController extends AbstractController

{

    public function login(Request $request, AuthenticationUtils $authUtils)

    {

        $username = $request->get('username');

        $password = $request->get('password');

        // ❌ Manual and unsafe login attempt

        if ($username && $password) {

            $user = $this->getDoctrine()

                         ->getRepository(User::class)

                         ->findOneBy(['username' => $username]);

            if ($user && $user->getPassword() === $password) {

                // Login logic (No hashing, no security)

                $session = $request->getSession();

                $session->set('user_id', $user->getId());

                return $this->redirectToRoute('dashboard');

            }

        }

        return $this->render('security/login.html.twig');

    }

}

❗ This is a classic Broken Authentication issue — no password hashing, no brute-force rate-limiting, and manual session handling.

✅ Secure Symfony Authentication Example

Symfony provides a secure built-in authentication system. Here's how you should properly configure authentication.

✅ security.yaml (firewall config)

security:

  encoders:

    App\Entity\User:

      algorithm: auto

  providers:

    users_in_db:

      entity:

        class: App\Entity\User

        property: email

  firewalls:

    main:

      anonymous: lazy

      provider: users_in_db

      form_login:

        login_path: login

        check_path: login

        csrf_token_generator: security.csrf.token_manager

      logout:

        path: logout

        invalidate_session: true

✅ User Entity with Hashed Password

use Symfony\Component\Security\Core\User\UserInterface;

use Symfony\Component\Validator\Constraints as Assert;

use Symfony\Component\Security\Core\User\PasswordAuthenticatedUserInterface;

class User implements UserInterface, PasswordAuthenticatedUserInterface

{

    // ...

    /**

     * @ORM\Column(type="string")

     * @Assert\NotBlank()

     */

    private $password;

    public function getPassword(): ?string

    {

        return $this->password;

    }

    public function setPassword(string $password): self

    {

        // Password will be encoded by Symfony encoder

        $this->password = $password;

        return $this;

    }

}

✔️ Symfony handles CSRF tokens, session management, and password hashing for you. Use its tools — don't reinvent the wheel.

📷 Screenshot: Free Website Security Checker Tool

Here is a screenshot of our free website security scanner, which detects Broken Authentication and other OWASP Top 10 vulnerabilities:

Screenshot of the free tools webpage where you can access security assessment tools.