Any software can be hit with malware. But the folks that target that type of behavior go for the highest common denominator when it comes to OS choices... and that still is Windows followed by MacOS.
That's why, as an example, even with the majority of internet sites being ran under Linux... what you see the Windows exploits that are taking down sites and being reported.
One of the biggest mistakes made (for server based stuff) was when Windows won out over OS/2.