Insecure object reference - Files

Need

Secure access control for files

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();

// Insecure object reference vulnerability
app.get('/user/:id', (req, res) => {
  const userId = req.params.id;
  const user = getUserById(userId); // Assuming this function retrieves user information from a database

  // Insecure access to user information
  res.send(user);
});

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

function getUserById(id: string) {
  // Database query to retrieve user information
  // This function does not validate the necessary permissions to access the user information
  return {
    id,
    name: 'John Doe',
    email: '[email protected]',
    role: 'user',
  };
}

The vulnerability in the provided code is an insecure object reference. This vulnerability occurs when an application allows unauthorized users to access or manipulate information of other users by simply knowing the identifier that differentiates them.

In this code, the vulnerability is present in the /user/:id route handler. When a user makes a GET request to this route with a specific user ID, the code retrieves the user information using the getUserById function. However, the code does not validate whether the user making the request has the necessary permissions to access the requested user's information.

This means that any user, even if they are not authorized, can access and view the account information of any other user by knowing their user ID. The user ID is directly taken from the request parameters without any validation or authorization checks.

This vulnerability can have a significant impact as it allows unauthorized users to access or manipulate sensitive information of other users. For example, an attacker can access personal details, modify account settings, or perform actions on behalf of other users.

To mitigate this vulnerability, it is recommended to implement proper authorization checks before allowing access to sensitive user information. The application should verify that the user making the request has the necessary permissions to access the requested user's information.

Steps

Implement a proper authentication and authorization mechanism in your application.
Ensure that the user making the request is authenticated and authorized to access the requested user information.
Validate the necessary permissions before retrieving and returning the user information.
Use a secure identifier for user identification, such as a UUID, instead of using sequential or predictable identifiers.
Consider implementing access control lists (ACLs) or role-based access control (RBAC) to manage user permissions.
Regularly review and update the access control mechanisms to ensure they are effective and up-to-date.

Compliant code

import express from 'express';

const app = express();

// Secure object reference vulnerability fixed
app.get('/user/:id', authenticateUser, authorizeUser, (req, res) => {
  const userId = req.params.id;
  const user = getUserById(userId); // Assuming this function retrieves user information from a database

  res.send(user);
});

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

function authenticateUser(req, res, next) {
  // Implement authentication logic here
  // Verify that the user making the request is authenticated
  // If not authenticated, return an error response or redirect to the login page
  // Example:
  if (!req.user) {
    return res.status(401).json({ message: 'Unauthorized' });
  }

  next();
}

function authorizeUser(req, res, next) {
  // Implement authorization logic here
  // Verify that the authenticated user has the necessary permissions to access the requested user information
  // If not authorized, return an error response or redirect to an error page
  // Example:
  if (req.user.role !== 'admin') {
    return res.status(403).json({ message: 'Forbidden' });
  }

  next();
}

function getUserById(id: string) {
  // Database query to retrieve user information
  // Validate the necessary permissions to access the user information
  // Example:
  if (req.user.id !== id && req.user.role !== 'admin') {
    throw new Error('Unauthorized access');
  }

  return {
    id,
    name: 'John Doe',
    email: '[email protected]',
    role: 'user',
  };
}

The fixed code addresses the insecure object reference vulnerability by implementing authentication and authorization checks before accessing user information.

The code defines an Express route handler for the '/user/:id' endpoint. This endpoint expects a user ID as a parameter.
The route handler is wrapped with two middleware functions: authenticateUser and authorizeUser. These functions are responsible for verifying the user's authentication and authorization, respectively.
The authenticateUser middleware checks if the user making the request is authenticated. If not, it returns a 401 Unauthorized response.
The authorizeUser middleware checks if the authenticated user has the necessary permissions to access the requested user information. In this example, it checks if the user's role is 'admin'. If not, it returns a 403 Forbidden response.
The getUserById function is responsible for retrieving user information from a database. It takes the user ID as a parameter. In this example, it also includes a permission check to ensure that only the user themselves or an admin can access the information.
If the authentication and authorization checks pass, the route handler retrieves the user information and sends it as a response.

By implementing authentication and authorization checks at both the middleware and function levels, the fixed code ensures that only authenticated and authorized users can access user information.

References

306.Insecure object reference - Files

Need​

Context​

Description​

Non compliant code​

Steps​

Compliant code​

References​