GraphQL Vulnerabilities: Common Risks And Attack Vectors

[Carolyn Miller]

Unauthorized GraphQL Query
One of the most dangerous GraphQL vulnerabilities occurs when users can send unauthorized queries. When a “GraphQL query is unauthorized” message appears, attackers can access sensitive data, bypassing authentication mechanisms. Without proper role-based access control (RBAC) or checks to make sure users can only access data they are authorized to view, attackers can easily query information such as personal data, financial records, or sensitive business data.

Excessive Data Exposure Through Nested Fragments
GraphQL’s ability to deeply nest fragments in queries, also known as nested fragment GQL, can lead to excessive data exposure. When clients are allowed to request deeply nested data without any limits, they can potentially expose more information than they need.

SQL Injection Risks In GraphQL Queries
GraphQL allows you to interact with databases, but without proper validation, SQL query within GraphQL schema vulnerabilities can occur. If user input isn’t sanitized or validated, attackers can inject malicious SQL commands into the query, bypassing GraphQL’s abstraction layer and compromising the underlying database.

Insufficient Query Complexity Checks
Another issue arises when GraphQL logic influences the request and response in ways that aren’t adequately controlled. A common attack is to send overly complex queries to overwhelm the server, consuming too much processing power and resulting in a denial of service (DoS) attack. Attackers can send queries with deeply nested fields and use fragments to make the query unnecessarily complex. These types of attacks exploit the flexibility of GraphQL to overwhelm server resources.

Cross-Site Scripting (XSS) in GraphQL
Although less common, GraphQL security issues in the body could lead to Cross-Site Scripting (XSS) vulnerabilities. This occurs when attackers inject malicious scripts into GraphQL queries that get executed in the client’s browser. XSS vulnerabilities typically arise when user inputs are not properly sanitized, so attackers can inject malicious scripts that could steal cookies and session tokens or perform other malicious actions. Proper input sanitization, output encoding, and avoiding JavaScript execution within the GraphQL responses are essential to preventing XSS attacks.