Re: Network drives and shares:
I've been told that crypto viruses only infect/encrypt network drives/shares that have been mapped to a drive letter.
If you don't map your drives but only access them by UNC path (or by shortcut to UNC path?) they won't be affected.
Does anyone know if this is true, for a fact? Or just internet myth?
AFAIK all crypto ransomware only encrypt files on network drives and shares mapped to the infected machine as drive letters. Dropbox accounts will also be affected if they are mapped.
By preventing temp applications from running in machine policy you can immunise from the whole class of malware.
CryptoPrevent does not work on CryptoWall 3.0 and some other newer crypto ransomware, unfortunately.