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. Change (...) ro quiet splash to (...) 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: passwd bitnami Reboot the virtual machine.
You should now have access to the bitnami user account with the new password.