I think by now every IT administrator knows about #WannaCry. If not, here are a few links:
The important thing ist, that the fix for Windows OS younger than Vista and Server 2008 and Vista is available since march. But the fix for XP and Server 2003 has only been published on Saturday I think. But it won’t appear on your WSUS until you import it manually, and you should do that right now!
Sorry for the German screenshots, but I think it will get you there!