Question: AppleMobileDeviceService.exe uses Half-Life server port number 27015
UDP port 27015 is the standard port used by Half-Life servers to communicate with clients.
TCP port 27015 seems to be used by AppleMobileDeviceService.exe to communicate locally with iTunes.exe and iTunesHelper.exe.
Since they are different protocols, there shouldn't be any conflict, but I haven't seen any mention of this in discussions I've found and I know a lot of people who, when the open up a firewall for a particular port, will open in for both UDP and TCP.
I don't know if this is a vulnerability, i.e. if an open firewall port would allow anything on the PC to be compromised, but I'm surprised Apple chose a port number which is so well-known, rather than a new arbitrary one, as there does seem to be the potential for a problem.
In any event, I intend to keep TCP port 27015 closed in my firewalls!
Fujitsu Siemens Amilo L 6825, Windows XP Pro, iPod touch