You don't. XProtectUpdater is probably what you are referring to, which is not the same as simply 'Xprotect'.
If you check your LittleSnitch details it will tell you that XProtectUpdater wants to connect to 'configuration.apple.com'. Which is fine, because it in actual fact is a list of sorts that Apple maintains to identify and deal with any potential malware. This is Apple's own description:
"Apple maintains a list of known malicious software that is used during the safe download check to determine if a file contains malicious software. The list is stored locally, and with Security Update 2011-003 is updated daily by a background process."
You can disable this in your System Preferences, but you probably shouldn't do that.