I don't know about the Cisco flavored Windows OS being "hardened" but I do know it doesn't contain unnecessary components. The more components removed from the OS allows for fewer things to be exploited. This is why you MUST get the patches for the OS from Cisco always and NEVER Microsoft.
We implement numerous "tech controls" for security purposes that harden the servers. Our security nazis wanted us to use the same controls for the Call Manager. We complied until we ran into problems with them. I guess what I'm saying is, based on my memory of the tech controls we tried, I don't think the Cisco OS is "hardened". I remmember one tech control was changing something like minimum password length...real basic things that a "hardened" OS would have as a standard.
Be sure to use the Cisco Security Agent always! No need to rate this post. I don't have a link to the requested documentation. I just thought I'd share a little of what I have experienced. : )
