The password for the default user, that is architech, is:
Host
architech
sudo is a program for Unix-like computer operating systems that allows users to run programs/commands with the security privileges of another user, normally the superuser or root. Not all the users can call sudo, only the sudoers, architech (the default user of the virtual machine) user is a sudoer. When you run a command preceeded by sudo Linux will ask you the user password, for architech user the password is architech.
By default, Ubuntu 12.04 32bit comes with no password defined for roor user, to set it run the following command:
Host
sudo passwd root
Linux will ask you (twice, the second time is just for confirmation) to write the password for user root.