A new ransomware strain called Locky hides in Microsoft Word files and encrypts all documents including unmapped network drives.
I’ve not seen this one yet, and hope I never do. This one appears to be viciously fast and quite pricey since Hollywood Presbyterian Medical Center paid the demanded ransom of 40 bitcoins — currently worth $16,664 according to NBC News.
Forbes has a shorter write up on this mess at http://www.forbes.com/sites/stevemorgan/2016/02/18/word-doc-can-shutdown-u-s-hospital-computers-and-cancer-treatment-equipment/#6f2943535141
The best bet to protect yourself and your network, don’t open those word files – and if you must open them DON’T enable the macros.