APIWeb ApplicationMarch 25, 2022Hacking GraphQL (Pt. 1)

In this blog post, we are going to use a publicly available application that uses a vulnerable GraphQL implementation, developed by .

GraphQL is quickly becoming the alternative to REST API, being able to request a specified set of data across multiple resources within a single request. But with great power come great security risks. A single point of failure could allow attackers to create complex queries and exhaust resources (DoS), or bypass authorization to retrieve unauthorized information.

What is GraphQL?

Excerpt from the official documentation:

GraphQL is a query language for your API, and a server-side runtime for executing queries using a type system you define for your data. GraphQL isn’t tied to any specific database or storage engine and is instead backed by your existing code and data.

Sample GraphQL Query:

Type of Requests:

        "title": "Learn GraphQL"
        "title": "Learn about queries"
  insert_todos(objects:[{title:"Learn GraphQL"}]){

Some common GraphQL endpoints:




Step 2: Send the HTTP request to Burp Repeater:



Step 3: Replace the POST body with a generic introspection query to fetch the entire backend schema. For this, we have used the ‘GraphQL Raider’ extension of Burp Suite.



Step 4: Capture the schema to gather sensitive API calls.



Sample Introspection Query:

{"query":"\n query IntrospectionQuery {\r\n __schema {\r\n queryType { name }\r\n mutationType { name }\r\n subscriptionType { name }\r\n types {\r\n ...FullType\r\n }\r\n directives {\r\n name\r\n description\r\n locations\r\n args {\r\n ...InputValue\r\n }\r\n }\r\n }\r\n }\r\n\r\n fragment FullType on __Type {\r\n kind\r\n name\r\n description\r\n fields(includeDeprecated: true) {\r\n name\r\n description\r\n args {\r\n ...InputValue\r\n }\r\n type {\r\n ...TypeRef\r\n }\r\n isDeprecated\r\n deprecationReason\r\n }\r\n inputFields {\r\n ...InputValue\r\n }\r\n interfaces {\r\n ...TypeRef\r\n }\r\n enumValues(includeDeprecated: true) {\r\n name\r\n description\r\n isDeprecated\r\n deprecationReason\r\n }\r\n possibleTypes {\r\n ...TypeRef\r\n }\r\n }\r\n\r\n fragment InputValue on __InputValue {\r\n name\r\n description\r\n type { ...TypeRef }\r\n defaultValue\r\n }\r\n\r\n fragment TypeRef on __Type {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n ofType {\r\n kind\r\n name\r\n }\r\n }\r\n }\r\n }\r\n }\r\n }\r\n }\r\n }\r\n ","variables":null}

The response may be quite big and hard to understand. The best way to understand the response is to visualize it. This can be done by using the ‘Voyager’ tool.





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Gaurav Patil

by Gaurav Patil

Associate Security Consultant | Redfox Security