How do you secure a MongoDB database?

// Create admin user
use admin
db.createUser({
  user: "admin",
  pwd: "securePassword",
  roles: ["root"]
});

// Create application user
use mydb
db.createUser({
  user: "appUser",
  pwd: "appPassword",
  roles: [{ role: "readWrite", db: "mydb" }]
});

// Built-in roles
// read, readWrite, dbAdmin, userAdmin, clusterAdmin, root

// Custom role
db.createRole({
  role: "readWriteOrders",
  privileges: [
    { resource: { db: "shop", collection: "orders" }, actions: ["find", "insert", "update"] }
  ],
  roles: []
});

// Assign role
db.grantRolesToUser("appUser", [{ role: "readWriteOrders", db: "shop" }]);

// With authentication
mongoose.connect('mongodb://user:password@localhost:27017/mydb?authSource=admin');

// With SSL
mongoose.connect('mongodb://localhost:27017/mydb', {
  ssl: true,
  sslValidate: true,
  sslCA: fs.readFileSync('/path/to/ca.pem')
});

# mongod.conf
net:
  bindIp: 127.0.0.1,10.0.0.1  # Limit to specific IPs
  port: 27017
  ssl:
    mode: requireSSL
    PEMKeyFile: /path/to/server.pem