1. The default user id and password for Cassandra DB is Cassandra, to authenticate using the default values you need to follow below steps.
2. Change authenticator option in the cassandra.yaml file to PasswordAuthenticator
3. By default its set to AllowAllAuthenticator
4. Change it to authenticator: PasswordAuthenticator
5. Restart Cassandra
6. Other option would be creating another superuser other than Cassandra