Graphql Introspection in Fiber with Cockroachdb

GraphQL introspection in a Fiber service that uses CockroachDB as the backend can expose metadata that assists an attacker in crafting targeted attacks. When introspection is enabled in production, an adversary can query the schema to discover types, queries, and field relationships. This can reveal patterns in how data is structured and how the application interacts with CockroachDB, potentially highlighting sensitive tables or operations that may lack proper authorization.

In a Fiber-based Go service, if the GraphQL endpoint is left permissive, introspection can return full type definitions, including arguments and return shapes. When combined with CockroachDB, this may expose naming conventions for database-backed models, such as table names or column families derived from the schema. Even without direct database access, these clues can feed into further enumeration, such as BOLA/IDOR or Property Authorization checks, because the API surface becomes more predictable.

For example, if your Fiber app uses a standard GraphQL resolver pattern to query CockroachDB, introspection might expose a User type with fields like id, email, and role. An attacker can infer that these fields are likely backed by a CockroachDB table named users, and if other protections (like rate limiting or strict authorization) are weak, the risk of unauthorized data access increases. middleBrick scans this attack surface during its 12 parallel checks, flagging GraphQL introspection as part of its inventory and input validation assessments, and mapping findings to frameworks like OWASP API Top 10 and SOC2.

middleBrick’s unauthenticated scan can detect whether introspection is enabled and report the associated risk, providing remediation guidance without requiring access to your CockroachDB instance. This is valuable because the combination of Fiber, GraphQL introspection, and CockroachDB can unintentionally create a roadmap for an attacker, even when the database itself is not directly exposed.

To mitigate GraphQL introspection risks in a Fiber service using CockroachDB, disable introspection in production and enforce strict schema design. Below are concrete code examples for a Fiber app using the graphql-go library with a CockroachDB connection.

1. Disable introspection in production

Configure your GraphQL server to disable introspection when not needed. In Go with graphql-go, you can achieve this by customizing the handler options.

package main

import (
	"github.com/gofiber/fiber/v2"
	"github.com/graph-gophers/graphql-go"
	"github.com/graph-gophers/graphql-go/relay"
)

func main() {
	app := fiber.New()

	// Define your schema with proper resolvers
	schema := graphql.MustParseSchema(`
	
type User {
		id: ID!
		email: String!
		role: String!
	}

	type Query {
		user(id: ID!): User
	}

	schema {
		query: Query
	}
	`, &resolver{})

	// Create a GraphQL handler with introspection disabled
	handler := relay.Handler{Schema: schema}
	app.Post("/graphql", func(c *fiber.Ctx) error {
		// Disable introspection explicitly in production
		opt := &graphql.ServerOpt{
			Resolver:               handler,
			DisableIntrospection:   true,
			DisableTracing:         true,
		}
		return graphql.NewServer(opt).ServeHTTP(c.Context().Response.Body())
	})

	app.Listen(":3000")
}

2. Use CockroachDB with parameterized queries and strict access controls

Ensure your database interactions avoid exposing schema details through error messages or logging. Use CockroachDB’s prepared statements and role-based access control.

-- CockroachDB SQL: create a restricted role for the Fiber app
CREATE ROIFIBERAPP WITH LOGIN PASSWORD 'secure_password';
GRANT SELECT ON TABLE users TO ROIFIBERAPP;
REVOKE ALL ON DATABASE mydb FROM ROIFIBERAPP;

In your Fiber service, use a database connection pool with this role and ensure queries are parameterized to avoid injection while keeping schema exposure minimal.

db, err := sql.Open("cockroachdb", "postgresql://rofib FiberApp:secure_password@localhost:26257/mydb?sslmode=require")
if err != nil {
	log.Fatal(err)
}
defer db.Close()

var user User
err = db.QueryRow("SELECT id, email, role FROM users WHERE id = $1", userID).Scan(&user.ID, &user.Email, &user.Role)
if err != nil {
	// Return generic error to avoid schema leakage
	c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "internal server error"})
	return
}

3. Validate and limit input to reduce attack surface

Combine Fiber middleware with schema-aware validation to ensure introspection is not abused even if accidentally enabled. middleBrick’s input validation checks can complement this by scanning your endpoint for unsafe consumption patterns.