Solaris use Role Based Access which is a better way to allow system access to defined users and only escalate permissions through roles. Kind of like sudo.

If you have an environment where you just don't care and want users to access the system like in a traditional root manner you can do the following:

<pre class="brush: bash; title: ; notranslate" title="">
# rolemod -K type=normal root
# grep PermitRoot /etc/ssh/sshd_config
PermitRootLogin yes
# svcadm refresh svc:/network/ssh:default