Honestly, I am not really sure how this is news? While it is true that malware and yes, botnets can be used on poorly secured servers run by inexperienced administrators, I really think this article is blowing things out of proportion.
What most people need to realize is that this is something that has both been around forever, in addition to targeting Windows PCs – not those running Linux. What is going to happen is the malicious user will be running the show via a Linux server. And again, all one needs to do is properly secure it in the first place.
In the end, no one single OS is going to be 100% secure. I have been saying this for years. But the truth of the matter, regardless as to why, is that Windows PCs are the target for malware, not those of the Linux variety.