Need

Protection of business information and user data confidentiality

Context

• Usage of TypeScript for statically typed JavaScript development
• Usage of Express for building web applications and APIs

Description

Non compliant code

        import express from 'express';

const app = express();

app.get('/users', (req, res) => {
  // Fetch and return the list of valid users
  const users = ['user1', 'user2', 'user3'];
  res.json(users);
});

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

The vulnerability in this code is a business information leak related to the list of valid users.

In the code, there is a route defined for /users which returns the list of valid users as a JSON response. The list of users is hardcoded in the code as ['user1', 'user2', 'user3'].

The issue with this code is that it exposes the list of valid users to anyone who accesses the /users endpoint. This can be a security risk as it allows potential attackers to gather information about the valid users of the system.

To fix this vulnerability, the code should implement proper access controls and authentication mechanisms to ensure that the list of valid users is only accessible to authorized individuals.

Steps

• Identify the sensitive business information that is being leaked. In this case, it is the list of valid users.
• Implement proper access controls to restrict access to the sensitive information. Only authorized users should be able to access the '/users' endpoint.
• Use authentication and authorization mechanisms to ensure that only authenticated and authorized users can access the '/users' endpoint.
• Implement role-based access control (RBAC) to define different levels of access for different users.
• Consider implementing encryption or obfuscation techniques to protect the sensitive information in transit and at rest.
• Regularly review and update the access controls to ensure they are effective and up-to-date with the changing business requirements.
• Consider implementing logging and monitoring mechanisms to detect and respond to any unauthorized access attempts or suspicious activities.
• Educate developers and stakeholders about the importance of protecting sensitive business information and the potential risks associated with its leakage.

Compliant code

        import express from 'express';

const app = express();

// Middleware for authentication and authorization
const authenticateUser = (req, res, next) => {
  // Implement your authentication logic here
  // For example, check if the user is logged in and has valid credentials
  // If not, return an error response or redirect to the login page
  // If the user is authenticated, call next() to proceed to the next middleware
  next();
};

// Middleware for role-based access control
const authorizeUser = (req, res, next) => {
  // Implement your authorization logic here
  // For example, check if the user has the necessary role or permissions to access the '/users' endpoint
  // If not, return an error response with a 403 Forbidden status code
  // If the user is authorized, call next() to proceed to the next middleware
  next();
};

app.get('/users', authenticateUser, authorizeUser, (req, res) => {
  // Fetch and return the list of valid users
  const users = ['user1', 'user2', 'user3'];
  res.json(users);
});

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

The fixed code addresses the vulnerability by implementing authentication and authorization middleware to protect the business information, specifically the list of valid users.

1. The code imports the 'express' module and creates an instance of the express application.

2. Two middleware functions, 'authenticateUser' and 'authorizeUser', are defined to handle authentication and authorization, respectively.

3. The 'authenticateUser' middleware is responsible for verifying the user's credentials and ensuring they are logged in. If the user is not authenticated, an error response or a redirect to the login page can be returned. If the user is authenticated, the middleware calls the 'next()' function to proceed to the next middleware.

4. The 'authorizeUser' middleware checks if the user has the necessary role or permissions to access the '/users' endpoint. If the user is not authorized, an error response with a 403 Forbidden status code can be returned. If the user is authorized, the middleware calls the 'next()' function to proceed to the next middleware.

5. The '/users' route is defined with the 'app.get()' method. It specifies that the route requires authentication and authorization by passing the 'authenticateUser' and 'authorizeUser' middleware functions as arguments. When a request is made to this route, the code fetches the list of valid users and returns it as a JSON response.

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

By implementing these middleware functions, the code ensures that only authenticated and authorized users can access the '/users' endpoint and retrieve the list of valid users. This helps protect the business information from unauthorized access.

References

• 221. Business information leak - Users