There is a ransomware raging across the globe currently, known as some variant of WannaCry, using an NSA exploit to infect Windows computers.  This particular exploit was patched in March so if you have Windows updates pending, make sure to get them installed or you might just have to pay to recover your data.  https://www.forbes.com/sites/thomasbrewster/2017/05/12/nsa-exploit-used-by-wannacry-ransomware-in-global-explosion/#75752440e599

More details from Ars Technica: https://arstechnica.com/security/2017/05/an-nsa-derived-ransomware-worm-is-shutting-down-computers-worldwide/