sbox is a CGI wrapper script that allows Web site hosting services to safely
grant CGI authoring privileges to untrusted clients. In addition to changing
the process privileges of client scripts to match their owners, it goes
beyond other wrappers by placing configurable ceilings on script resource
usage, avoiding unintentional (as well as intentional) denial of service
attacks. It also optionally allows the Webmaster to place client's CGI
scripts in a chroot'ed shell restricted to the author's home directories.

sbox is compatible with all Web servers running under BSD-derived flavors of
Unix. You can use and redistribute it freely.

WWW: http://stein.cshl.org/WWW/software/sbox/