To reset the passwords on IPBrick (Debian) you will need to edit the default Grub menu at the boot screen.
Select the kernel and the Grub Boot screen and press e
Locate the kernel line of and enter
init=/bin/bash
at the very end.
press
CTRL-X
The server will then boot at drop you at the command prompt.
Enter the following to reset the passwords and reboot the server
mount -rw -o remount / mount /usr /usr/bin/passwd username
[ you will now be prompted to confirm and change the password]
shutdown -r -n now
The server will now reboot and you can login locally with the passwords you have just set.