In case you want to remove the banner, you will just need to SSH into your machine and then execute the following command:
First connect to your instance in AWS from the EC2 panel. Select connect. Then copy the command.
You need to change the permissions on the key file first
chmod 400 WILICSI.pem ssh -i "WILICSI.pem" firstname.lastname@example.org
sudo /opt/bitnami/apps/wordpress/bnconfig --disable_banner 1
Please note that /opt/bitnami is the default installation directory of the Bitnami stack.
Finally, you need to restart Apache.
sudo /opt/bitnami/ctlscript.sh restart apache
You will find more information about the Bitnami banner using the following link: