In the below announcement Microsoft steps down from providing support for Windows XP. This announcement was initially made in early 2014.
http://windows.microsoft.com/en-us/windows/end-support-help
Latest update includes security updates, i.e. the complete absence of any going forward. In summary, XP’s security is worse than ever and will continue to get worse.
http://www.zdnet.com/article/windows-xp-security-just-got-worse-again/
What makes this situation curious, is the fact that according to Net Applications, XP still has roughly 16% desktop marketshare. That’s more than enough to keep botmasters busy for as long as those machines will be around.
This would be a perfect time for beefing up security in respect to traffic coming from XP machines.