A few links, because the topic has already been discussed so much that I do not feel like writing a long post…

http://sekurak.pl/uwaga-ransomware-atakuje-poprzez-najnowsza-dziure-we-flashu/

http://sekurak.pl/jak-bezpieczniej-surfowac-dzieki-click-to-play/

https://helpx.adobe.com/security/products/flash-player/apsb15-14.html

Information on how to verify the Flash version.