Overall, we can't say that we don't like the Vista Ultimate code that was released to manufacturing by Microsoft Wednesday and will subsequently be available for corporate volume customers by the end of the month. After all, from our testing we can confirm that it contains vastly improved graphics, offers very flexible installation options, and gives administrators stronger control over the operating systems security settings.

However, in our extensive tests of this code on a variety of platforms we found that many of the Vista Ultimate default settings are plainly dangerous. That, coupled with the fact that Microsoft now offers a variety a means for enforcing its new security controls, means enterprise administrators will need to make a significant effort to pull off a secure Vista Ultimate deployment.

We also found Vista Ultimate's much needed hierarchical user security model -- called User Access Control (UAC) -- will likely become problematic in a widespread deployment from both systems security and administrative points of view. Historically, many Windows-based applications have presumed they be given the 'right' to root access to some operating system features. When an application does this on a machine running Vista Ultimate, the attempt triggers an automatic response (the text for which is often cryptic and offers only a registry entry when a user requests "Details" regarding an "exception" pop-up message) from the operating system that asks the user if this access should be granted and demands some level of administrative password to complete a requested operation desired by an application. Both good software as well as malware in our testing consistently provoked these messages and subsequent choices.

Although users of Windows XP SP2 may be used to root-access intervention messaging, Vista Ultimate goes much further, preventing even with some of its own utilities from effecting changes to the underlying operating system without user or administrator permission. The temptation is to accept, rather than reject, these requests in order to get access to the applications users will need. The downside to that decision would be letting a virus, Trojan, or malware application infect the system through the front door despite the presence of Windows Defender anti-malware application and in spite of numerous security settings put in place by a careful administrator.

We were easily able to infect our Vista Ultimate machines with variations of the Blaster Trojan by letting an application proceed as described. Microsoft elected to lay this decision on the hapless user and their support mechanisms, rather than force thousands of applications vendors to modify their code to behave in a hierarchical user access model.

Unless administrators pre-load all possible enterprise applications before the end users get their new Vista Ultimate machines, any application exception will require mitigation by administrative/help desk support personnel, because users won't know what to do when presented with the options.

We also found issues with how Vista Ultimate in combination with the new Internet Explorer 7 handles digital certificate interactions with SSL-protected Web sites and services. Vista Ultimate and Internet Explorer 7 change the way digital certificates are processed and can cause error messages that don't typically provide details about the certificate in question. Users or administrators have almost no information with which to debug the sometimes thorny PKI problems that SSL can cause, let alone track down attackers who attempt to spoof sites by using invalid/inappropriate certificates.