Checklist Schema Discovery and Analysis: Utilize introspection to discover and analyze available queries, mutations, and types. (Tools: InQL Scanner, GraphQL Voyager; Example command: { __schema { types { name, fields { name, type { name } } } }} to gather comprehensive schema information) Testing for Introspection: Ensure introspection queries are disabled in production to protect schema details. (Tools: Burp Suite, custom scripts; Example command: Attempt introspection with {__schema{types{name}}} and ensure it returns an error in production environments.) Authentication and Authorization Testing: Verify security mechanisms to ensure only authorized access to resources. (Tools: Burp Suite, OWASP ZAP; Example command: Attempt to fetch sensitive data without authentication or with an expired token to test access controls.) Batch Query Testing: Test for potential denial of service (DoS) through batched queries and deeply nested queries. (Tools: Custom scripts, GraphQL Fuzzer; Example command: { user(id:"1"){ friends { friends { friends { id } } } } } to test server response to deep nesting) Query Depth Limit: Verify that depth limiting is in place to prevent overly complex queries from overloading the server. (Tools: Burp Suite, custom middleware; Example setup: Configure depth limiting in GraphQL server settings and attempt to exceed this limit to test enforcement.) Field Suggestion Testing: Ensure that automatic field suggestions are disabled to prevent information leakage. (Tools: Manual testing, Burp Suite; Example test: Access the API with a graphical IDE like GraphiQL to see if sensitive fields are suggested.) Alias Overloading: Check for abuse of aliases to perform unauthorized actions or to bypass security controls. (Tools: Burp Suite, GraphQLmap; Example command: { user(id: "1") { id, username } newUser: user(id: "2") { id, username } } to test how aliases are handled.) Mutation Testing: Test mutation operations for security issues, ensuring they properly check permissions before executing changes. (Tools: Burp Suite, OWASP ZAP; Example command: mutation { updatePassword(id: "1", newPass: "123456") { success } } to check if unauthorized password changes are allowed.) Error Handling: Analyze error messages to ensure they do not disclose sensitive information about the GraphQL schema or underlying systems. (Tools: Manual testing, Burp Suite; Example test: Force errors in queries and observe error messages for hints about backend details or schema structure.) Rate Limiting: Evaluate the implementation of rate limiting to mitigate abuse scenarios. (Tools: Burp Suite Intruder, custom rate limit testers; Example command: Execute a script that makes repeated requests to a GraphQL endpoint to test if and when rate limiting kicks in.) Subscription Security: Verify the security of subscription operations, ensuring they are restricted to authorized users only. (Tools: Manual testing, custom scripts; Example test: Attempt to access subscription data streams without proper credentials.) Input Validation: Test for common vulnerabilities like SQL injection, XSS through inputs in GraphQL queries. (Tools: GraphQLmap, Burp Suite; Example command: Include malicious payloads in query variables to test sanitization, e.g., { user(id: "1' OR '1'='1") { name } }) Query Cost Analysis: Perform cost analysis on queries to ensure they don't lead to resource exhaustion. (Tools: Apollo Engine, custom scripts; Example command: Analyze the cost of complex queries to ensure they are within acceptable limits, adjust settings if necessary.) Compliance Checks: Ensure that GraphQL operations comply with regulatory requirements such as GDPR. (Tools: Manual review, compliance software; Example command: Review all data handling practices in GraphQL queries to ensure compliance with data protection regulations.) Documentation Review: Review documentation for accuracy and unintentional exposure of sensitive details. (Tools: Manual review; Example command: Cross-reference published schema details with documentation to ensure no additional information is leaked.) Third-Party Libraries: Examine all third-party libraries for known vulnerabilities. (Tools: OWASP Dependency Check, Retire.js; Example command: Run dependency-check against the server environment to detect outdated or vulnerable libraries.) Direct Object Reference Tests: Test for unauthorized access to objects via direct references. (Tools: Burp Suite, custom scripts; Example command: Change IDs in queries to test for unauthorized data access, e.g., { user(id: "5") { name } } where '5' is not authorized.) Logging Mechanisms: Ensure that all actions, especially mutations, are logged correctly to trace malicious activities. (Tools: ELK Stack, custom logging solutions; Example setup: Configure GraphQL server to log all query and mutation requests along with user context.) Response Timing Analysis: Analyze response times to infer backend processing and to identify potential vulnerabilities like timing attacks. (Tools: Custom timing analysis scripts, Burp Suite; Example command: Measure response times for different query loads to detect discrepancies that may indicate backend processing issues.) Stateful Inspection of Sessions: Check how the API handles session state, particularly in authentication and re-authentication scenarios. (Tools: Burp Suite, custom scripts; Example command: Test session tokens before and after re-authentication to ensure tokens are refreshed or invalidated as necessary.) API Gateway Integration: Test integration with API gateways to ensure that security policies are correctly enforced. (Tools: AWS API Gateway, Azure API Management; Example setup: Configure rate limiting and authentication at the gateway level and test for enforcement.) Dynamic Query Analysis: Examine how the API handles dynamically constructed queries and prevent potential injection or abuse. (Tools: Custom scripts, Burp Suite; Example command: Construct queries dynamically on the client-side and monitor for improper handling or execution.) Mutation Side-Effects: Test mutations for unintended side effects that could impact data integrity or user experience. (Tools: Burp Suite, custom test suites; Example command: Perform a mutation and verify all related entities to ensure only intended changes are made.) Query Whitelisting: Implement and test a whitelisting approach where only pre-approved queries are allowed. (Tools: GraphQL Shield, custom middleware; Example setup: Define a list of allowed queries and block all others at runtime.) Schema Change Management: Monitor and audit changes to the GraphQL schema to prevent unauthorized alterations. (Tools: Schema change detection tools, version control systems; Example command: Set up alerts for any commits to schema files in version control.) Deprecation Strategy: Test how deprecated queries and fields are handled to ensure they don't introduce security vulnerabilities. (Tools: Manual testing, GraphQL IDE tools; Example command: Mark certain fields as deprecated in the schema and verify they are no longer accessible or visible in production.)