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

If introspection is enabled, the server will return a massive JSON response containing the entire schema structure. Use tools to visualize and parse this data:

• GraphQL Voyager: Paste the JSON response into GraphQL Voyager to graphically map the database relationships.
• InQL (Burp Extension): Automatically detects introspection queries and generates a mock structure of all queries and mutations in your Repeater tab.

Phase 4: Bypassing Disabled Introspection

If the server responds with a syntax error or "GraphQL introspection is not allowed", check for partial introspection or use dictionary attacks.

• Field Suggestion (Clairvoyance): If you misspell a field, GraphQL might say Did you mean "email"?. Tools like Clairvoyance or GraphW00f can brute force and reconstruct the schema based on these error messages.

Decision Point 🔀

flowchart TD
    A[Discover /graphql Endpoint ] --> B{Introspection Enabled? ]}
    B -->|Yes| C[Send Full __schema Query ]
    B -->|No| D[Test Field Suggestion Errors ]
    C --> E[Map Queries/Mutations ]
    D -->|Errors exist| F[Brute-force Schema (Clairvoyance) ]
    D -->|No Errors| G[Manual Fuzzing ]
    E & F --> H[Hunt for IDOR / Logic Bugs ]

🔵 Blue Team Detection & Defense

• Disable Introspection in Production: Disable Field Suggestions: Implement Rate Limiting and Depth Limits: Key Concepts | Concept | Description | |---------|-------------|

Output Format

Graphql Introspection Abuse — Assessment Report
============================================================
Target: [Target identifier]
Assessor: [Operator name]
Date: [Assessment date]
Scope: [Authorized scope]
MITRE ATT&CK: [Relevant technique IDs]

Findings Summary:
  [Finding 1]: [Severity] — [Brief description]
  [Finding 2]: [Severity] — [Brief description]

Detailed Results:
  Phase 1: [Phase name]
    - Result: [Outcome]
    - Evidence: [Screenshot/log reference]
    - Impact: [Business impact assessment]

  Phase 2: [Phase name]
    - Result: [Outcome]
    - Evidence: [Screenshot/log reference]
    - Impact: [Business impact assessment]

Risk Rating: [Critical/High/Medium/Low/Informational]
Recommendations:
  1. [Immediate remediation step]
  2. [Long-term hardening measure]
  3. [Monitoring/detection improvement]

📚 Shared Resources

For cross-cutting methodology applicable to all vulnerability classes, see:

• _shared/references/elite-chaining-strategy.md — Exploit chaining methodology and high-payout chain patterns
• _shared/references/elite-report-writing.md — HackerOne-optimized report writing, CWE quick reference
• _shared/references/real-world-bounties.md — Verified disclosed bounties by vulnerability class

References

• PortSwigger: GraphQL API vulnerabilities
• GitHub: InQL Scanner