Microsoft Tuesday released 11 security patches, six with the highest rating of "critical" that span Windows, Office, and Internet Explorer, but some say it is a combination of two non-critical vulnerabilities that should catch the eye of corporate IT.

Of the six critical vulnerabilities, none of them require any more user interaction than opening a document or visiting a malicious Web site. All six allow the attacker to take complete control of a user’s machine.

The vulnerabilities affecting Internet Explorer as part of bulletin MS08-010 are troubling, according to experts, because of the wide-spread use of both IE 6 and 7, which are both at risk. (Compare Patch and Vulnerability Management products.)

“In the past, a lot of the IE stuff has been around the scripting engines, but this is in the core HTML rendering engine,” says Don Leatham, director of solutions and strategy at Lumension Security.

Office, another widely used client, is vulnerable in critically rated patches MS08-008, 009, 012 and 013.

Click to see: List of patches Microsoft sent out

“I would tell my mom to install 010 first, but for corporate users they should install 006 and 005 first,” says Eric Schultze, CTO of Shavlik Technologies. He says MS08-005 and MS08-006, while rated important, can be viewed as critical vulnerabilities since they allow a hacker to gain control of a Web server and to escalate privileges from “user” to “admin.”

“With the combination of 006 and 005, I can remotely attack your Web site and become an administrator,” says Schultze. “Each one is rated ‘important,’ but I call them critical in both cases.”

“006 is back to the days of Code Red where you can execute code on a Web server,” says Schultze. “That means I can execute TFTP (Trivial File Transfer Protocol) and have TFTP come back to my machine and upload hacker tools. I can end up with a C prompt of your Web server. I can have shell access to your Web server as a user. I call that critical right away. I can install a port redirector on that system so I can attack other system in the DMZ and use the port redirector to bypass your firewalls and filtering rules.”

Shultze says the final dagger comes with patch 005.

“Combine that with 005, which allows a user of a Web server to become administrator of a Web server. So I just hacked you with 006 and now as a user I can run more code to become an admin.”