Sign in Subscribe
2 min read

Secure your APIs: Preventing entity ID tampering and unauthorized Access

In today’s connected world, securing your APIs is critical. Attackers often exploit weaknesses like entity ID tampering or injection attacks to access or manipulate data they shouldn’t. Whether you’re building an e-commerce platform, social media, or any user-centric app, proper authorization checks and input sanitization are must-haves.

Let’s dive into some common scenarios and best practices to safeguard your backend and frontend from these threats.

Protect entity access by verifying ownership

Imagine a user wants to update their order, profile, or any resource linked to them. If your API blindly trusts the entity ID provided, a malicious user could tamper with the ID and access or modify someone else’s data.

What to do:

  • Always check the ownership or association of the entity against the authenticated user’s ID.
  • For example, if you have a order resource with an owner_id, verify:

// Pseudocode example in a Node.js backend
const order = await db.getOrderById(orderId);
if (order.owner_id !== req.user.id) {
  return res.status(403).json({ error: 'Access denied' });
}

This simple check ensures only the rightful owner can access or modify their data.

Prevent Injection Attacks and XSS vulnerabilities

Attackers can inject malicious scripts or SQL code through seemingly innocent input fields like sign-up forms, comments, or posts.

Common Injection Risks:

  • SQL Injection: where attackers insert SQL statements that manipulate your database.
  • Cross-Site Scripting (XSS): where attackers inject JavaScript to steal cookies, session tokens, or manipulate the DOM.

How to prevent:

  • Use parameterized queries or ORM query builders that automatically sanitize inputs.
  • For example, in SQL (using parameterized queries):

SELECT * FROM users WHERE email = $1;
  • On the frontend and backend, sanitize user input before rendering or saving it.
  • Use libraries like DOMPurify to clean HTML content submitted by users (e.g., comments, posts).

const cleanInput = DOMPurify.sanitize(userInput);
  • Set proper HTTP headers like Content Security Policy (CSP) to restrict script execution sources.

Additional real-world security practices

  • Rate limiting - prevent brute force or spam attacks by limiting how often a user can hit your API.
  • Authentication & Authorization - never trust client-side controls alone, always enforce authorization on the server.
  • Validate all inputs - never trust data coming from the client. Use strict schema validation (e.g., Joi, Yup).
  • Avoid exposing sensitive data - be mindful about what data your API returns; don’t leak user emails, tokens, or internal IDs unnecessarily.
  • Use HTTPS everywhere - protect data in transit from man-in-the-middle attacks.
  • Log suspicious activity - monitor failed access attempts and anomalous behavior for early detection.
  • Secure session management - use httpOnly, secure cookies, and short session timeouts.

Summary

Securing your APIs against entity ID tampering and injection attacks requires careful validation, authorization, and sanitization. Always verify ownership on every resource access, clean and validate all user inputs, and adopt additional best practices like rate limiting and secure session handling.

By integrating these measures, you protect your users’ data and maintain trust in your application.

Want to dive deeper?

If you want to strengthen your security skills and get detailed, practical examples on how to protect your React, Next.js, Express, or NestJS applications, check out these excellent resources:

Feel free to explore these guides to boost your app’s security from the frontend to the backend!

Published by:

Volodymyr Osmin

Member discussion