Apple has released Security Update 2003-12-19, which delivers a number of security enhancements and is recommended for all Mac OS X users. According to the release notes, the update includes the following components: AFP Server, ASN.1 Decoding for PKI, cd9660.util, Directory Services, fetchmail, fs_usage, rsync, and System Initialization. The 3.6MB download is available via the Software Update preference pane.