An Austrian hacker earned the dubious distinction of writing what are thought to be the first known viruses for Microsoft's  Windows Vista operating system. Written in July, the viruses take advantage of a new command shell, code-named Monad, that is included in the Windows Vista beta code.

The viruses were published last month in a virus-writing tutorial written for an underground hacker group calling itself the Ready Ranger Liberation Front, and take advantage of security vulnerabilities in the new command shell. Unlike the traditional Windows graphical user interface, which relies heavily on the mouse for navigation, command shells allow users to use powerful text-based commands, much like Windows' predecessor, DOS.

The viruses were written by a hacker calling himself "Second Part To Hell," and published on July 21, just days after Monad was publicly released by Microsoft, according to Mikko Hyppönen, chief research officer with Helsinki's F-Secure Corp. Second Part To Hell is the pseudonym of an Austrian-based hacker who also goes by the name Mario, Hyppönen said.

Because of its sophistication, the new command shell offers new opportunities for hackers, Second Part To Hell wrote in the tutorial, a copy of which was obtained by the IDG News Service. "Monad will be like Linux's BASH (Bourne Again Shell) -- that means a great number of commands and functions," he wrote. "We will be able to make as huge and complex scripts as we do in Linux."

F-Secure has named the virus family Danom (Monad in reverse). After examining the code, Hyppönen said that the Danom family is disruptive, but not capable of causing significant damage to Windows users. "These are proof of concept viruses," he said, "Where virus writers want to break new ground and write the first viruses for a new platform."