I suspect Google are looking at this, but I is likely to be difficult to Fix.
The only way to kill the Botnet is for Microsoft to rollout an update to WindowsDefender or WindowsUpdate, or for the ISP`s to cutoff the Broadband connections, or for the Botnet Command&Control server to be shut down. All of these factors are outside of Google`s control, and the Standard user-agents and diversity of IP`s, makes this traffic difficult to diferentiate vs human visitors. Thus I suspect, it is also difficult to track down the source on a network level. Additionally, as Chrome is not effected - only Microsoft will have access to IE status reports on browser settings and plugins.