Don't know where you got that info from but it's wrong: "The latest Symantec technologies and Norton consumer and Symantec enterprise solutions protect against these kinds of attacks"
Cryptolocker: A Thriving Menace | Symantec Connect Community
Trojan.Cryptolocker | Symantec
No anti-virus product can protect you against all threats as there is always a window of opportunity between discovery of a new threat or variation of existing threats and the update making it onto your system.
This looks a useful tool to use to block the sort of behaviour demonstrated by Cryptolocker and many other malwares:
CryptoPrevent | Computer Technician - PC Repair Software |Foolish IT LLC