Requirements for a suid script include:

• #! directing the KornShell be used
• Executable by user, group, and other
• No read permission
• Add suid permission by chmod u+s on the file

Add a -p option to #! to increase security to force a separate process if one is not normally done.

Example:

#! /usr/bin/ksh -p

Source of this information:

http://www.ibm.com/developerworks/aix/library/au-kornshell93.html#n