There is a malware exploit going around that is targeting Synology NAS's. It basically puts a version of Cryptolocker on the NAS, rendering all your files useless.
http://www.theregister.co.uk/2014/08..._as_you_think/
Patch and turn off your NAS as a precaution. I don't own one of these but I know Synology is a popular model.