For Solaris only:
Need physical or remote console access to the system to use these steps:

1. Press Stop-A on the console or Ctrl-] and send brk from a remote console connection to access the Open Boot Prompt (OBP)
2. Insert a bootable Solaris CD and boot into single-user mode with boot cdrom -s
3. Make a mount point within the /tmp file system by typing mkdir /tmp/mnt
4. Mount the root partition of the boot disk in /tmp/mnt.
ex. mount /dev/dsk/c0t0d0s0 /tmp/mnt
5. Edit /etc/shadow with vi /tmp/mnt/etc/shadow
6. Remove the encrypted part of the root password (the second field; fields are separated by colons), save, and exit
7. Unmount the file system with umount /tmp/mnt
8. Reboot the system and assign a new password at a shell prompt with the passwd command

If you are unable to run vi above, you can edit /etc/shadow using the ed editor

# ed /tmp/mnt/etc/shadow
1p
s/:………….:/::/ (Note: there are 13 dots in the second field)
1p
w
q