Apple has released the aptly named "Security Update 2002-09-20." The update provides security enhancements that mainly affect the Terminal. From the Software Update Control Panel notes (and the ReadMe installed in the Receipts folder for the update):
Security Update 2002-09-20 includes the following updated components which provide increased security to prevent unauthorized access to applications, servers, and the operating system.
[Apps updated] Terminal
You can get the update through the Software Update Control Panel.