GraphQL Circular Reference

Remediation

To prevent GraphQL circular reference attacks, implement query depth and complexity controls:

1. Implement query depth limiting: Set maximum query depth to prevent infinite recursion through circular references.

   Example (GraphQL Depth Limit):

   const depthLimit = require('graphql-depth-limit');
      
   const server = new ApolloServer({
     typeDefs,
     resolvers,
     validationRules: [depthLimit(10)] // Limit depth to 10 levels
   });
   

2. Use query complexity analysis: Implement complexity analysis that accounts for circular references and nested relationships.

   Example (GraphQL Query Complexity):

   const { costAnalysisPlugin } = require('graphql-cost-analysis');
      
   const server = new ApolloServer({
     typeDefs,
     resolvers,
     plugins: [
       costAnalysisPlugin({
         maximumCost: 1000,
         defaultCost: 1,
         fieldCosts: {
           User: {
             friends: { cost: 10 }, // Higher cost for potentially recursive fields
             posts: { cost: 5 }
           }
         }
       })
     ]
   });
   

3. Implement circular reference detection: Create custom validation rules to detect and prevent circular reference patterns.

   Example (Custom circular reference detection):

   const circularReferenceRule = (context) => {
     const visitedTypes = new Set();
        
     return {
       Field(node, key, parent, path, ancestors) {
         const fieldName = node.name.value;
         const parentType = context.getParentType();
            
         if (parentType && visitedTypes.has(parentType.name + '.' + fieldName)) {
           context.reportError(
             new GraphQLError('Circular reference detected', [node])
           );
         }
            
         visitedTypes.add(parentType.name + '.' + fieldName);
       }
     };
   };
   

4. Set execution timeouts: Configure query execution timeouts to prevent long-running circular queries.

About

GraphQL circular reference vulnerabilities occur when the GraphQL schema contains types that reference each other in a way that allows infinite recursion. For example, a User type that has friends of type User, or a Post type that has comments that can have replies, creating potentially infinite nested structures. Attackers can exploit these circular relationships by crafting deeply nested queries that traverse the circular references repeatedly, causing resource exhaustion, stack overflow errors, or denial of service. This vulnerability is particularly common in social media applications, content management systems, or any schema that models hierarchical or interconnected data structures.

Risks

The risks associated with GraphQL circular reference vulnerabilities include:

• Resource exhaustion: Circular queries can consume excessive CPU, memory, and database resources by creating deeply nested result sets or infinite loops.
• Stack overflow: Deep recursion through circular references can cause stack overflow errors, potentially crashing the GraphQL server or application.
• Database overload: Circular reference queries may generate complex JOIN operations or recursive database queries that can overwhelm database servers.
• Denial of service: Malicious circular reference queries can render the application unavailable by exhausting server resources or causing system crashes.