graphql-introspection-abuse

GraphQL Introspection Abuse

When to Use

• During the reconnaissance phase of evaluating web applications that utilize GraphQL.
• To rapidly map the API surface area without relying on brute-force directory or endpoint enumeration.
• To visualize the API schema and identify potentially vulnerable data relationships and administrative mutations.

Prerequisites

• Authorized scope and target URLs from bug bounty program
• Burp Suite Professional (or Community) configured with browser proxy
• Familiarity with OWASP Top 10 and common web vulnerability classes
• SecLists wordlists for fuzzing and enumeration

Workflow

Phase 1: Identifying GraphQL Endpoints

Common endpoints include /graphql, /api/graphql, /v1/graphql, /v2/graphql, and sometimes /gql.

Phase 2: Sending the Introspection Query

The standard GraphQL Introspection query requests the __schema field.

// Concept: Request schema metadata {
  "query": "query IntrospectionQuery { __schema { queryType { name } mutationType { name } types { ...FullType } } } fragment FullType on __Type { kind name fields(includeDeprecated: true) { name args { ...InputValue } type { ...TypeRef } } } fragment InputValue on __InputValue { name type { ...TypeRef } defaultValue } fragment TypeRef on __Type { kind name ofType { kind name ofType { kind name } } }"
}

Send this POST request to the endpoint:

# curl -X POST -H "Content-Type: application/json" -d '{"query":"\n    query IntrospectionQuery {\n      __schema {\n        queryType { name }\n        mutationType { name }\n        subscriptionType { name }\n        types {\n          ...FullType\n        }\n      }\n    }\n\n    fragment FullType on __Type {\n      kind\n      name\n      description\n      fields(includeDeprecated: true) {\n        name\n        args {\n          ...InputValue\n        }\n      }\n    }\n    fragment InputValue on __InputValue {\n      name\n    }\n  "}' http://target.local/graphql

Phase 3: Analyzing the Schema