"Then they own the domain," Schultze says. "By owning it they then have domain admin privileges, which means they own every laptop and server and desktop in that domain. They can create user accounts, they can delete everybody's user accounts, they can lock everybody off the server, they can delete fields, they can add and delete services and they control everything in the domain."

Another potentially dangerous vulnerability lies in Host Integration Server RPC Service (MS08-059), which is another remote execution bug. The vulnerability covers 2000, 2004 and 2006 version of host integration server.

"Control of HIS can give an attacker control of data flowing into and out of some of the most closely guarded systems on the planet," Sheldon Malm, director of security R&D for nCircle, wrote in a research note. "It is absolutely vital for customers to find and remediate this vulnerability as quickly as possible. Host Integration Server is the de facto gateway linking Windows hosts to business critical mainframes and AS/400 systems, which in turn host databases and Customer Information Control System (CICS) applications that are believed to run in 90% of Fortune 500 corporations."

The other critical patches are a cumulative update for Internet Explorer (MS08-058) that resolves five privately reported vulnerabilities and one that was publicly disclosed.

The vulnerabilities, however, cut a wide swath across Internet Explorer.