You probably should change the default password though.
If an attacker somehow managed to get traffic past your router's firewall, then the mister's weak password might give them a foothold in your home network.
Granted the mister is unlikely to be online 24/7, and it's running a very cut-down version of linux so it would be of limited use to an attacker, but best to be safe.
If you're using a windows PC, download "putty" ssh client and use it to connect as user "root" to your mister's IP address in the form "192.168.x.x".
From a mac/linux launch a terminal and type "ssh
root@192.168.x.x".
Once connected to the mister, type "passwd root" and enter a new password.
Updates to the linux part of mister sometimes reset the password back to "1", meaning you have to modify it again.