I don want to open my TeraStation. Is it still possible to become root?
Yes. See the previous question regarding modifying a firmware image and applying it. As it’s possible to make your own (hacked) firmware, the old answers have been removed. On some firmware versions you can exploit loopholes in the software to become root. On the TeraStation Pro II it´s just a matter of running ACP Commander. After that you have telnet running and you can connect as root, with no password.