A new strain of ransomware has hit the internet recently. At the moment it seems constrained to Eastern Europe and has infected the Kiev metro system and Odessa airport.
The Infection starts with a fake Adobe Flash installation that is downloaded from hacked websites. The download file contains all the tools to spread itself and encrypt your data.
If you are asked by a website to update or download a Flash update please contact you IT support and DO NOT download until it has been checked.