Apple iTunes before 8.0 on Mac OS X 10.4.11, when iTunes Music Sharing is enabled but blocked by the host-based firewall, presents misleading information about firewall security, which might allow remote attackers to leverage an exposure that would be absent if the administrator were given better information.
http://www.securityfocus.com/bid/31090
http://securitytracker.com/id?1020840
http://lists.apple.com/archives/security-announce//2008/Sep/msg00001.html