API Security

GraphQL Security Testing: From Introspection to Data Exfiltration

January 202514 min read

The Shift to GraphQL

GraphQL offers developers a flexible and efficient way to query APIs. However, this flexibility introduces new attack vectors that are often overlooked during traditional security testing.

Introspection: The Attacker's Map

GraphQL's introspection feature allows anyone to query the schema and understand all available types, queries, and mutations. If left enabled in production, it's a goldmine for attackers.

Insecure Direct Object References (IDOR)

IDOR is just as prevalent in GraphQL as it is in REST. Attackers can manipulate arguments in queries or mutations to access data they shouldn't have access to.

Batching Attacks

GraphQL allows multiple queries to be sent in a single request. Attackers can use this to perform brute-force attacks or exfiltrate large amounts of data while bypassing rate limits.

Nested Query Denial of Service (DoS)

Complex, deeply nested queries can consume significant server resources. Without proper depth limiting, an attacker can crash the server with a single, well-crafted query.

Securing GraphQL APIs

Key defensive measures include disabling introspection in production, implementing robust authorization at the resolver level, and enforcing query depth and complexity limits.