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Authentication mechanism absence or evasion

Need​

Implementation of a robust and secure authentication mechanism

Context​

  • Usage of TypeScript for type-checking and compiling JavaScript code
  • Usage of Express for building web applications and APIs

Description​

Non compliant code​

import express from 'express';

const app = express();

// Vulnerable route without authentication
app.get('/admin', (req, res) => {
  res.send('Welcome to the admin panel!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

The vulnerability in this code is the absence of an authentication mechanism for the '/admin' route. The route is accessible to anyone without requiring any form of authentication or session initialization. This means that an attacker can easily bypass the login mechanism and gain unauthorized access to the admin panel.

Without proper authentication, sensitive information or critical functionality within the admin panel can be accessed, modified, or abused by unauthorized users. This can lead to unauthorized data manipulation, privilege escalation, or even complete compromise of the application.

To mitigate this vulnerability, it is recommended to implement a strong authentication process for the '/admin' route. This can include requiring users to provide valid credentials, such as a username and password, and verifying them against a secure user database. Additionally, it is important to ensure that each user attempting to access the admin panel has an initialized session, which can be done by implementing session management techniques.

Steps​

  • Implement a strong authentication mechanism for accessing the '/admin' route.
  • Ensure that only authenticated users with valid sessions can access the '/admin' route.
  • Use a session management library or framework to handle user sessions.
  • Store session data securely and validate session tokens to prevent session hijacking or tampering.
  • Consider implementing additional security measures such as rate limiting, IP blocking, and user role-based access control.
  • Regularly update and patch the authentication mechanism to address any security vulnerabilities.

Compliant code​

import express from 'express';
import session from 'express-session';

const app = express();

// Session configuration
app.use(session({
  secret: 'your-secret-key',
  resave: false,
  saveUninitialized: false,
}));

// Middleware to check if user is authenticated
const isAuthenticated = (req, res, next) => {
  if (req.session && req.session.user) {
    return next();
  }
  res.status(401).send('Unauthorized');
};

// Protected route with authentication
app.get('/admin', isAuthenticated, (req, res) => {
  res.send('Welcome to the admin panel!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

The fixed code addresses the vulnerability by implementing a strong authentication mechanism using sessions in an Express.js application.

First, the code imports the necessary modules, including express and express-session.

Then, an Express application is created using express().

The code sets up session configuration using the express-session middleware. The secret option is used to provide a secret key for session encryption. The resave option is set to false to prevent session data from being saved on every request. The saveUninitialized option is also set to false to prevent uninitialized sessions from being saved.

Next, a middleware function called isAuthenticated is defined. This middleware checks if the user has an active session by verifying if req.session.user exists. If the user is authenticated, the middleware calls the next() function to proceed to the next middleware or route handler. If the user is not authenticated, a 401 Unauthorized response is sent.

The code then defines a protected route /admin that requires authentication. The isAuthenticated middleware is added as a second argument to the route handler. This ensures that only authenticated users can access the admin panel. If the user is authenticated, the route handler sends a response with the message "Welcome to the admin panel!".

Finally, the application listens on port 3000 and logs a message to indicate that the server is running.

By implementing sessions and requiring authentication for protected routes, the fixed code ensures that unauthorized access to critical functionality is prevented.

References​

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