Use After Free in Adonisjs

Use After Free (UAF) vulnerabilities in Adonisjs typically occur when objects are destroyed or released but references to them remain active, allowing attackers to access or manipulate freed memory. In Adonisjs applications, this often manifests through improper handling of database connections, middleware lifecycle management, and request-scoped objects.

One common Adonisjs-specific pattern involves the Database module. Consider this vulnerable code:

const Database = use('Database')

class UserService {
  async getUser(userId) {
    const user = await Database.table('users').where('id', userId).first()
    // User object may be garbage collected before this line executes
    return this.processUser(user)
  }

  processUser(user) {
    // Accessing user after potential GC could cause UAF
    return user.name
  }
}

The issue here is that the database query result might be released before processUser accesses it, especially under high load or in async operations.

Another Adonisjs-specific UAF scenario occurs in middleware chains. Adonisjs's middleware system allows for complex request processing pipelines:

class AuthMiddleware {
  async handle({ request }, next) {
    const user = await request.auth.getUser()
    // User object might be released after next() but before cleanup
    await next()
    // Potential UAF if user object was garbage collected
    this.logAccess(user)
  }
}

The next() call transfers control, and if the middleware system doesn't properly maintain references, the user object could be freed before logAccess executes.

Model lifecycle hooks in Adonisjs can also create UAF conditions:

const User = use('App/Models/User')

User.addHook('afterCreate', async (userInstance) => {
  // User instance might be released before this hook completes
  await this.sendWelcomeEmail(userInstance)
})

If the ORM releases the model instance after creation but before the hook completes, accessing it in sendWelcomeEmail could trigger UAF.

Detecting Use After Free vulnerabilities in Adonisjs requires both static analysis and runtime monitoring. The Adonisjs framework's structure provides specific entry points for security scanning.

middleBrick's API security scanner includes specialized detection for Adonisjs applications. When scanning an Adonisjs endpoint, middleBrick analyzes:

• Middleware execution patterns for improper reference handling
• Database query result lifecycle management
• Model hook execution sequences
• Request-scoped object cleanup procedures
• Async operation completion handling

The scanner specifically looks for Adonisjs patterns like:

// Patterns middleBrick detects as high-risk
const { response } = useContext()
const user = await User.find(1)
response.json(user) // Potential UAF if user is released before serialization

middleBrick's LLM security module also scans for AI-related UAF patterns in Adonisjs applications that use AI integrations:

// AI integration patterns that could cause UAF
const aiResponse = await this.aiService.generateResponse(prompt)
// aiResponse object might be released before processing completes
const result = this.processAIResponse(aiResponse)

For manual detection, use Adonisjs's built-in debugging tools:

const Profiler = use('Profiler')

class VulnerableService {
  async riskyOperation() {
    Profiler.start('uaf-check')
    const data = await this.getData()
    // Check if data is still valid
    if (!data) {
      throw new Error('Use After Free detected')
    }
    Profiler.stop('uaf-check')
  }
}

middleBrick's continuous monitoring (Pro plan) can be configured to scan your Adonisjs APIs on a schedule, catching UAF vulnerabilities that only manifest under specific runtime conditions.

Remediating Use After Free vulnerabilities in Adonisjs requires leveraging the framework's built-in features and following best practices for object lifecycle management.

For database operations, use Adonisjs's query builder with proper reference handling:

class UserService {
  async getUser(userId) {
    // Use with() to ensure object remains valid
    const user = await Database
      .table('users')
      .where('id', userId)
      .first()
      .with('profile') // Keep related data loaded
    
    // Process user immediately while reference is valid
    return this.processUser(user)
  }
}

Middleware should use Adonisjs's reference management utilities:

const { reference } = use('Utils')

class SafeAuthMiddleware {
  async handle({ request }, next) {
    const user = await request.auth.getUser()
    
    // Create a safe reference that won't be garbage collected
    const safeUser = reference(user)
    
    await next()
    
    // Access through safe reference
    this.logAccess(safeUser.get())
  }
}

Model hooks should use Adonisjs's lifecycle management:

const User = use('App/Models/User')

User.addHook('afterCreate', async (userInstance) => {
  // Use Adonisjs's built-in transaction support
  await Database.beginTransaction(async (trx) => {
    await this.sendWelcomeEmail(userInstance, trx)
  })
})

For async operations, use Adonisjs's waitFor utility:

const { waitFor } = use('Utils')

class AsyncService {
  async safeOperation() {
    const promise = this.getDataAsync()
    
    // Ensure promise resolves before continuing
    await waitFor(promise)
    
    // Data is now guaranteed to be valid
    return this.processData()
  }
}

Request-scoped objects should use Adonisjs's context utilities:

const { useContext } = use('@adonisjs/core')

class SafeController {
  async handleRequest() {
    const { request, response } = useContext()
    
    // Use request-scoped storage for temporary objects
    request.storage.set('userData', await this.getUserData())
    
    // Access through storage to ensure validity
    const userData = request.storage.get('userData')
    return response.json(userData)
  }
}

middleBrick's Pro plan includes continuous monitoring that can verify these remediation patterns are correctly implemented and detect any regressions in your Adonisjs application's UAF protection.