The default password for Cassandra is Cassandra. So we need to change it immediately after we install it. We can use this command to change it.
Change default password for Cassandra user
# cqlsh `hostname` -u cassandra
Password:
Connected to xxx at xxx-xxx-xxx-2.localdomain:9042.
[cqlsh 5.0.1 | Cassandra 2.2.13 | CQL spec 3.3.1 | Native protocol v4]
Use HELP for help.
cassandra@cqlsh>
cassandra@cqlsh> ALTER USER cassandra with PASSWORD ‘xxxx#####xxxxxxx’;
cassandra@cqlsh> exit