Fixing OWASP API1:2023 — Broken Object Level Authorization in Symfony 7

What a Simple Mistake Can Lead To

Generated with DALL-E

Introduction

Symfony 7 is a powerful framework that makes building RESTful APIs a breeze. But with great power comes great responsibility — security pitfalls can sneak into your code if you’re not careful.

One of the most common vulnerabilities in APIs is Broken Object Level Authorization (API1:2023) from the OWASP API Security Top 10, where attackers can access or manipulate data they shouldn’t.

In this article, we’ll:

1. Build a simple JSON REST CRUD API.
2. Show how it accidentally breaks API1:2023.
3. Explain the problem in plain English.
4. Fix it with a secure solution.

By the end, you’ll have a working API and a solid understanding of how to protect it.

What is Broken Object Level Authorization (API1:2023)?

Before we code, let’s understand the enemy. Broken Object Level Authorization happens when an API lets users access or modify resources (like database records) they don’t own or aren’t authorized to touch.

Imagine a user changing someone else’s profile just by tweaking an ID in a request. That’s the flaw we’ll first create, then fix.

Step 1: Setting Up a New Symfony 7 Project

First, we need to create a new Symfony 7 project. The easiest way is to use the Symfony CLI, a great tool for managing Symfony applications.

If you don’t have it installed, download it from the official Symfony website.

Open your terminal and run this command to create a new project:

symfony new 34-api-security-api1

This command will create a new bare minimum Symfony app.

You can test if the app was created successfully by starting the built-in server. Navigate to the 34-api-security-api1 directory in the terminal and run this command:

symfony serve