MongoDB Authentication

Secure your MongoDB with proper authentication.

Quick Start

Enable Authentication

# Start MongoDB with authentication
mongod --auth --dbpath /data/db

# Or in config file (mongod.conf)
security:
  authorization: enabled

Create Admin User

// Connect to local server without auth first
const mongo = new MongoClient('mongodb://localhost:27017')
const admin = mongo.db('admin')

// Create admin user
await admin.command({
  createUser: 'admin',
  pwd: 'securepassword',  // Or use passwordPrompt()
  roles: ['root']
})

// Now restart mongod --auth

Authentication Methods

SCRAM (Salted Challenge Response)

// Default, password-based authentication

// Connection string
mongodb://username:password@localhost:27017/database

// With options
mongodb://username:password@localhost:27017/database?authSource=admin

// Create SCRAM user
db.createUser({
  user: 'appuser',
  pwd: 'password123',
  roles: ['readWrite']
})

X.509 Certificate

// Enterprise-grade certificate authentication

// Create certificate user (External auth DB)
db.getSiblingDB('$external').createUser({
  user: 'CN=client,OU=Engineering,O=Company',
  roles: ['readWrite']
})

// Client connects with certificate
mongodb://USERNAME@cluster.mongodb.net/?authMechanism=MONGODB-X509&tlsCertificateKeyFile=/path/to/client.pem

LDAP

// Enterprise directory integration

// Create LDAP user (External auth DB)
db.getSiblingDB('$external').createUser({
  user: 'ldapuser',
  roles: ['readWrite']
})

// Configure LDAP in mongod.conf
security:
  ldap:
    servers: 'ldap.example.com'
    authzQueryTemplate: 'dc=example,dc=com??sub?(uid={0})'
    bindQueryUser: 'cn=admin,dc=example,dc=com'
    bindQueryPassword: 'password'

User Management

Create User

// Basic user
db.createUser({
  user: 'username',
  pwd: 'password',
  roles: ['readWrite']
})

// With multiple roles
db.createUser({
  user: 'dbadmin',
  pwd: 'password',
  roles: [
    { role: 'dbAdmin', db: 'myapp' },
    { role: 'readWrite', db: 'myapp' }
  ]
})

// Interactive password prompt
db.createUser({
  user: 'username',
  pwd: passwordPrompt(),
  roles: ['readWrite']
})

List Users

// Show all users in current database
db.getUsers()

// Show specific user
db.getUser('username')

Update User Password

// Change password
db.changeUserPassword('username', 'newpassword')

// Or
db.updateUser('username', {
  pwd: 'newpassword'
})

Remove User

db.dropUser('username')

Built-in Roles

Database User Roles

'read' → Read-only access
'readWrite' → Read and write access

// Grant role
db.grantRolesToUser('username', ['read'])

Database Admin Roles

'dbAdmin' → Database administration
'dbOwner' → Full database access
'userAdmin' → User management

// Example
db.createUser({
  user: 'dbadmin',
  pwd: 'password',
  roles: ['dbAdmin', 'userAdmin']
})

Cluster Admin Roles

'clusterAdmin' → Full cluster access
'clusterManager' → Cluster management
'clusterMonitor' → Read-only monitoring

// Cluster role
db.getSiblingDB('admin').createUser({
  user: 'clusteradmin',
  pwd: 'password',
  roles: ['clusterAdmin']
})

All Built-in Roles

Admin: root, dbAdmin, userAdmin, clusterAdmin
Read: read
Write: readWrite
Backup: backup, restore
Monitoring: clusterMonitor, serverStatus, monitoring

Custom Roles

Create Custom Role

// Create custom 'reportViewer' role
db.createRole({
  role: 'reportViewer',
  privileges: [
    {
      resource: { db: 'reporting', collection: '' },
      actions: ['find']
    }
  ],
  roles: []
})

// Assign to user
db.grantRolesToUser('analyst', [
  { role: 'reportViewer', db: 'admin' }
])

Privilege Structure

{
  resource: {
    db: 'myapp',           // Database ('' = all dbs)
    collection: 'users'    // Collection ('' = all collections)
  },
  actions: [
    'find',        // Query documents
    'insert',      // Insert documents
    'update',      // Update documents
    'remove',      // Delete documents
    'createIndex', // Index management
    'dropIndex'
  ]
}

Password Policies

Strong Passwords

// Requirements for production:
// ✅ Minimum 12 characters
// ✅ Mix of uppercase, lowercase, numbers, symbols
// ✅ No dictionary words
// ✅ Not related to username

// Example strong password
// P@ssw0rd2024!MongoDB

// DON'T USE
// password, 123456, monkey, qwerty, password123

Password Rotation

// Change passwords regularly
// Monthly for service accounts
// Quarterly for normal users

// Update password
db.changeUserPassword('username', 'newpassword')

// Check user details
db.getUser('username')

Connection with Authentication

MongoDB Shell

# Connect with authentication
mongosh --username admin --password --authenticationDatabase admin mongodb://localhost:27017

# Or with connection string
mongosh 'mongodb://admin:password@localhost:27017/?authSource=admin'

Node.js Driver

const MongoClient = require('mongodb').MongoClient

// Option 1: Connection string
const client = new MongoClient(
  'mongodb://username:password@localhost:27017/database?authSource=admin'
)

// Option 2: With encodeURIComponent for special chars
const user = encodeURIComponent('user@example.com')
const pass = encodeURIComponent('pass!@#$%')
const client = new MongoClient(
  `mongodb://${user}:${pass}@localhost:27017/database?authSource=admin`
)

// Option 3: Auth options
const client = new MongoClient('mongodb://localhost:27017', {
  auth: {
    username: 'admin',
    password: 'password'
  },
  authSource: 'admin'
})

Python PyMongo

from pymongo import MongoClient

# Connection string
client = MongoClient('mongodb://username:password@localhost:27017/database?authSource=admin')

# Or with options
client = MongoClient(
    'mongodb://localhost:27017',
    username='username',
    password='password',
    authSource='admin'
)

Security Best Practices

✅ User Management:

1. Unique passwords – Each user gets own password
2. Strong passwords – 12+ chars, complex
3. Regular rotation – Change periodically
4. Least privilege – Only needed roles
5. Separate accounts – Admin vs. app users

✅ Production Security:

1. Always enable auth – –auth or authorization: enabled
2. Use network authentication – Bind to specific IPs
3. Enable TLS/SSL – Encrypt connections
4. Regular audits – Check user permissions
5. Disable default users – Remove guest, test users

✅ Atlas Security:

1. Enable SCRAM – Default method
2. Use strong passwords – Auto-generated preferred
3. Create service accounts – For applications
4. Limited roles – readWrite for apps, not admin
5. Monitor activity – Check who accessed what

❌ Avoid:

1. ❌ Sharing passwords
2. ❌ Weak passwords
3. ❌ No authentication
4. ❌ Admin credentials for apps
5. ❌ Hardcoded passwords in code

Next Steps

1. Enable authentication – On your MongoDB
2. Create admin user – Initial setup
3. Create app user – For application
4. Test connection – From application
5. Setup TLS – Encrypt connections
6. Monitor users – Who can access what

Secure your MongoDB with authentication! 🔐