One of my clients has lost the password of the Debian. You may reset it by
Configure the GRUB boot loader to boot directly to the Bash shell in read-write mode as the root user. To do this:
Boot the virtual machine and immediately press the Esc key to load the boot menu.
Type e to edit the boot commands.
Navigate down the menu until you are on the line starting with kernel.
Type e to edit that line.
(...) ro quiet splash
(...) rw init=/bin/bash
Save the change with the Enter key.
Boot the system with the b key.
NOTE: The changes made are temporary and will be reset after a reboot.
Once the system boots to a Bash shell, run the command below and enter a new password when prompted:
Reboot the virtual machine.
You should now have access to the bitnami user account with the new password.