One of the days to remember in history is 12/05/2017, on that day the world cried fowl to cyber attack known as ransomware wannacry. In that incident more than 200,000 computers were encrypted from more than 150countries.
Windows OS was affected most since most companies were using the obsolete Windows XP. Though Microsoft had stopped updates for WindowsXP, it has released the security patches for WindowsXP alongside other regular updates to cater for other Windows versions.
In this case, users of WindowsXP are required to download and install the security patches to ensure safety against attacks. The download is available in two options, you can use Microsoft download center(here) or update catalog.
For those using Windows 8.1 or 10 supporting auto update don't need to bother to take any action. For users managing their updates manually are required to update their systems to the latest to overcome the risks of cyber attacks.