Good ones here:
https://www-secure.symantec.com/connect/articles/how-harden-cryptolocker-file-encoding-attempts-sepm-application-control
https://www-secure.symantec.com/connect/articles/detecting-cryptolocker-activity-symantec-endpoint-protection
https://www-secure.symantec.com/connect/articles/strengthening-anti-virus-security-prevent-ransom-ware-derivative-trojancryptolocker-family-
and here:
https://www-secure.symantec.com/connect/articles/ac-and-hi-policy-help-ransomware