Cryptolocker prevention using SEP on workstation ?

People,

Can anyone please assist me in what is the SYmantec steps & procedure in SEP 12.1.6 to prevent cryptolocker virus encrypting the file server content from users PC ?

Over the weekend, one of the user in my company got infected thus from his PC or through terminal server with just AV component enabled, the file server mapped network drive is now encrypted.

Note, SEP client is v12.1.5

Thanks.