🚀 csrf-shield - CSRF Protection Middleware

csrf-shield is a middleware for protecting web applications from Cross-Site Request Forgery (CSRF) attacks. It integrates easily with Express.js and ensures that your forms and requests are secure.

📦 Installation

Install csrf-shield via npm or Yarn.

NPM

npm install csrf-shield

Yarn

yarn add csrf-shield

🛠️ Usage

Basic Setup

Here’s a step-by-step guide on how to set up csrf-shield in an Express.js application:

1. Create a basic Express.js application.

2. Integrate csrf-shield middleware for CSRF protection.

3. Use the CSRF token in your forms and validate it on the server side.

Example Code

Below is a complete example of how to use csrf-shield with an Express.js application:

const express = require('express');
const csrfProtection = require('csrf-shield')({
    secret: 'your_secret_key', // Optional: Set a custom secret key for encryption
    timeout: 1000 * 60 * 10, // Optional: Set token validity period (10 minutes)
});
const bodyParser = require('body-parser');

const app = express();

// Use body-parser middleware to parse form and JSON data
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

// Use CSRF protection middleware
app.use(csrfProtection.middleware);

app.get('/', (req, res) => {
    res.send(`
        <form method="post" action="/login">
            <input type="text" name="username" />
            <input type="password" name="password" />
            <input type="hidden" name="_csrf" value="${req.csrfToken()}" />
            <button type="submit">Login</button>
        </form>
    `);
});

app.post('/login', csrfProtection.verifyToken(), (req, res) => {
    res.send('Logged in');
});

app.listen(3000, () => {
    console.log('Server started on http://localhost:3000');
});

Key Points:

• secret: (Optional) The secret key used for encrypting and decrypting CSRF tokens. It's recommended to set a custom, secure key. If not provided, a random key will be generated automatically.
• timeout: (Optional) The validity period of tokens in milliseconds. Default is 10 minutes. Adjust this value according to your application's security needs.

Generating CSRF Tokens

To generate CSRF tokens, use the following method:

app.use((req, res, next) => {
    req.csrfToken = () => {
        const ip = req.headers['cf-connecting-ip'] || req.headers['x-forwarded-for'] || req.ip;
        const userAgent = req.headers['user-agent'];
        return csrfProtection.generateToken(ip, userAgent);
    };
    next();
});

Token Verification

Use the verifyToken middleware to verify tokens in your routes:

app.post('/login', csrfProtection.verifyToken(), (req, res) => {
    res.send('Logged in');
});

🔍 Features

• Automatic Token Generation: Generates a CSRF token for each request.
• Token Verification: Validates tokens in requests and checks their validity.
• Customizable: Set your own secret key and token validity period.

⚠️ Why Use This?

CSRF attacks exploit the trust a web application has in the user's browser. csrf-shield helps prevent these attacks by ensuring that every request with sensitive actions is accompanied by a valid CSRF token.

📄 API Reference

csrfShield(options)

• options.secret: (Optional) The secret key used for encrypting tokens. A random key is used by default if not specified.
• options.timeout: (Optional) The validity period of tokens in milliseconds. Default is 10 minutes.

middleware(req, res, next)

• req.csrfToken(): Generates a new CSRF token to be used in forms.

verifyToken()

• req.body._csrf: (Optional) Token location in form data.
• req.query._csrf: (Optional) Token location in query parameters.
• req.headers['x-csrf-token']: (Optional) Token location in HTTP headers.

🛠️ Support & Contributing

For issues or contributions, please visit the GitHub repository.

📝 License

This project is licensed under the MIT License.