How a GraphQL Misconfiguration Exposed Sensitive Information: A $25,000 Bug Bounty Report

Discovering and Exploiting Insecure GraphQL Endpoints for Unauthorized Data Access

Introduction

GraphQL is a powerful API query language that enables clients to request exactly the data they need. However, misconfigurations in GraphQL implementations can expose sensitive data, private program details, and internal structures to unauthorized users.

A security researcher recently discovered a critical GraphQL vulnerability that allowed unauthorized access to sensitive information from private programs. By enumerating GraphQL object IDs, they were able to reveal program names, scope details, and private report titles, leading to a $25,000 bug bounty reward.

This article explores how this vulnerability worked, how attackers exploit GraphQL misconfigurations, and how to secure GraphQL APIs from such attacks.

1️⃣ Understanding GraphQL and Its Security Risks

🔹 What is GraphQL?

GraphQL is a query language for APIs that allows clients to request specific data rather than receiving a fixed response like REST APIs.

💡 Example GraphQL Query:

{
  "query": "{user(id: 1) {name, email, role}}"
}

The API only returns requested fields, reducing data transfer overhead.

🔹 Common Security Risks in GraphQL APIs

GraphQL provides flexibility but also introduces new security challenges, including:

❌ Insecure Direct Object References (IDOR): Attackers can guess and manipulate object IDs to access unauthorized data.
❌ Overly Permissive Queries: APIs may allow unauthenticated access to sensitive data.
❌ Lack of Rate Limiting: Attackers can brute-force GraphQL queries to extract data.
❌ Introspection Enabled in Production: Attackers can enumerate all available queries and objects, exposing API structure.

2️⃣ Exploiting the GraphQL Vulnerability: How…