GraphQL security best practices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to limit the maximum query depth in a GraphQL server.

GraphQL

const depthLimit = require('graphql-depth-limit');
const server = new ApolloServer({
  schema,
  validationRules: [[1](5)]
});

Drag options to blanks, or click blank then click option'

AdepthLimit

BmaxDepth

ClimitDepth

DdepthCheck

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent function name like maxDepth.

Forgetting to wrap the function call with parentheses.

The depthLimit function is used to limit the maximum depth of a GraphQL query to prevent overly complex queries.

2fill in blank

medium

Complete the code to enable query complexity analysis in a GraphQL server.

GraphQL

const queryComplexity = require('graphql-query-complexity');
const server = new ApolloServer({
  schema,
  validationRules: [queryComplexity({
    maximumComplexity: [1],
    onComplete: (complexity) => console.log('Query Complexity:', complexity)
  })]
});

Drag options to blanks, or click blank then click option'

A10

B10000

C1000

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the complexity too high, which defeats the purpose.

Setting the complexity too low, which may block valid queries.

Setting maximumComplexity to 100 helps prevent very expensive queries that could overload the server.

3fill in blank

hard

Fix the error in the code to properly disable introspection in a GraphQL server.

GraphQL

const { ApolloServerPluginLandingPageDisabled } = require('apollo-server-core');
const server = new ApolloServer({
  schema,
  plugins: [[1]()]
});

Drag options to blanks, or click blank then click option'

AApolloServerPluginIntrospectionDisabled

BApolloServerPluginLandingPageDisabled

CDisableIntrospectionPlugin

DIntrospectionOffPlugin

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent plugin name.

Forgetting to call the plugin as a function.

The ApolloServerPluginLandingPageDisabled plugin disables the GraphQL playground and introspection queries for security.

4fill in blank

hard

Fill both blanks to implement rate limiting middleware for a GraphQL server.

GraphQL

const rateLimit = require('express-rate-limit');
const limiter = rateLimit({
  windowMs: [1],
  max: [2]
});
app.use('/graphql', limiter);

Drag options to blanks, or click blank then click option'

A15 * 60 * 1000

B100

C1000

D60 * 1000

Attempts:

3 left

💡 Hint

Common Mistakes

Setting windowMs to seconds instead of milliseconds.

Setting max too high or too low.

The windowMs is set to 15 minutes (15 * 60 * 1000 ms), and max is set to 100 requests per window to limit client requests.

5fill in blank

hard

Fill all three blanks to add authentication and authorization checks in a GraphQL resolver.

GraphQL

const resolvers = {
  Query: {
    user: (parent, args, context) => {
      if (!context.[1]) {
        throw new Error('Not authenticated');
      }
      if (!context.user.[2].includes('admin')) {
        throw new Error('Not authorized');
      }
      return getUserById(args.id);
    }
  }
};

Drag options to blanks, or click blank then click option'

AisAuthenticated

Broles

Cpermissions

Dauth

Attempts:

3 left

💡 Hint

Common Mistakes

Checking authorization before authentication.

Using incorrect property names in context.

The context.isAuthenticated checks if the user is logged in, context.user.roles holds user roles, and includes('admin') checks if the user has admin rights.

Practice

1. What is the main purpose of authentication in GraphQL security?

easy

A. To encrypt the data sent between client and server

B. To limit the number of queries a user can make

C. To verify the identity of the user making the request

D. To format the GraphQL schema correctly

Solution

1. Step 1: Understand authentication role

   Authentication checks who the user is before allowing access.

2. Step 2: Differentiate from other security measures

   Limiting queries and encryption are different security aspects, not authentication.

3. Final Answer:

   To verify the identity of the user making the request -> Option C

4. Quick Check:

   Authentication = Verify user identity [OK]

Hint: Authentication means checking who you are [OK]

Common Mistakes:

• Confusing authentication with authorization
• Thinking authentication limits query size
• Mixing authentication with encryption

2. Which of the following is the correct way to limit query complexity in a GraphQL server?

easy

A. Allow unlimited queries and rely on client honesty

B. Use SQL injection to filter queries

C. Disable authentication to speed up queries

D. Use a middleware that calculates query depth and rejects too deep queries

Solution

1. Step 1: Identify query complexity control

   Middleware can analyze query depth and reject overly complex queries to protect the server.

2. Step 2: Eliminate incorrect options

   Allowing unlimited queries or disabling authentication weakens security; SQL injection is an attack, not a defense.

3. Final Answer:

   Use a middleware that calculates query depth and rejects too deep queries -> Option D

4. Quick Check:

   Limit query complexity = Middleware checks depth [OK]

Hint: Middleware can block too complex queries [OK]

Common Mistakes:

• Ignoring query complexity limits
• Confusing SQL injection with security measure
• Disabling authentication to improve speed

3. Given this GraphQL resolver snippet, what will happen if a user without proper role tries to access the data?

const resolver = (parent, args, context) => {
  if (!context.user.roles.includes('admin')) {
    throw new Error('Access denied');
  }
  return getData();
};

medium

A. An error 'Access denied' will be thrown for non-admin users

B. The data will be returned regardless of user role

C. The server will crash due to missing roles

D. The resolver will ignore the role check and return null

Solution

1. Step 1: Analyze role check in resolver

   The code checks if the user roles include 'admin'. If not, it throws an error.

2. Step 2: Understand error handling

   Throwing an error stops execution and returns 'Access denied' to the client.

3. Final Answer:

   An error 'Access denied' will be thrown for non-admin users -> Option A

4. Quick Check:

   Role check fails = Error thrown [OK]

Hint: Throw error if user lacks role [OK]

Common Mistakes:

• Assuming data returns without role check
• Thinking server crashes on missing role
• Believing null is returned instead of error

4. Identify the security issue in this GraphQL server setup:

const server = new ApolloServer({
  typeDefs,
  resolvers,
  context: ({ req }) => ({ user: req.user })
});

// No rate limiting or query complexity checks applied

medium

A. Missing authentication in context setup

B. No rate limiting or query complexity protection

C. Resolvers are not defined

D. Using ApolloServer is insecure

Solution

1. Step 1: Review context and security features

   Context passes user info, so authentication may exist, but no rate limiting or complexity checks are shown.

2. Step 2: Identify missing protections

   Without rate limiting and query complexity checks, server is vulnerable to overload and abuse.

3. Final Answer:

   No rate limiting or query complexity protection -> Option B

4. Quick Check:

   Missing limits = Vulnerable server [OK]

Hint: Always add rate limits and complexity checks [OK]

Common Mistakes:

• Assuming ApolloServer is insecure by default
• Confusing missing resolvers with security issue
• Ignoring rate limiting importance

5. You want to protect your GraphQL API from abuse by limiting both query complexity and request rate. Which combination of methods is best practice?

hard

A. Implement query depth analysis middleware and use a rate limiter like Redis to track requests

B. Only use authentication tokens without any query or rate limits

C. Disable introspection to prevent all queries

D. Allow unlimited queries but log all requests for later review

Solution

1. Step 1: Understand query complexity protection

   Middleware that analyzes query depth helps prevent expensive queries that overload the server.

2. Step 2: Understand rate limiting

   Using a rate limiter like Redis tracks and limits how many requests a user can make in a time window.

3. Step 3: Evaluate other options

   Authentication alone doesn't limit abuse; disabling introspection breaks development; logging alone doesn't prevent abuse.

4. Final Answer:

   Implement query depth analysis middleware and use a rate limiter like Redis to track requests -> Option A

5. Quick Check:

   Combine depth check + rate limiter = Best protection [OK]

Hint: Use middleware plus rate limiter for best security [OK]

Common Mistakes:

• Relying only on authentication
• Disabling introspection breaks tools
• Logging without limiting requests