The part that makes this really nasty is it doesn't just impact webservers. IIS is highly leveraged by other Microsoft technologies, everything from WSUS to SMTP to Exchange to Sharepoint are affected. In my environment, I estimate that 3/4 of my servers are vulnerable.
They really should have made it clear that it's a mitigating factors and that most (some, many?) non-IIS uses wouldn't use kernel caching and thus be OK.
