CryptoLocker

POSSIBLE DUPLICATE

http://www.theguardian.com/money/2013/oct/19/cryptol...

http://www.theguardian.com/money/2013/oct/19/10-ways...

I don't know how applicable this is to Macs, but I would rather not find out the hard way.

It would make me nervous to have an external hard drive or Time Machine always connected to a Mac or any PC.

I wonder if the suggested use of Google Mail is worthwhile.

I believe that CryptoLocker only targets Windows machines. But ransomware like this is a growing threat, and there is no reason that it could not target OS X (there have been some fairly high profile ransomware instances on OS X). So all it takes is for some bright spark to have the idea of marrying OS X ransomware with encryption and the result will be the same.

The moral is clear. Whatever OS you use, don't open email attachments unless you are 100% sure of their provenance. In particular, bin anything purporting to come from your bank or a Government agency if it contains an attachment (and/or, never click on any links in such an email). If in doubt you should check the email headers to see where the message really comes from.

No OS is proof agains social engineering.

I would second the above comments but also add that you should back up important stuff to disc, I think dvd's are best at they cannot be infected by a trojan and necessitate using a new disc each time thus giving you periodical backups.