Windows PowerShell isn't soup yet. But virus writers already have created a proof-of-concept worm that targets the Microsoft's scripting shell, formerly code-named "Monad." PowerShell is slated to debut as part of Exchange Server 2007 in late 2006 or early 2007.

The tool gained instant notoriety last summer after security vendor F-Secure sighted the first proof-of-concept virus and referred to it as Damon. The company mistakenly labelled it as the world's first virus for Windows Vista. The Damon virus was developed by the same group of malware authors as this year's Cibyz virus. However, the new version is more advanced, said Allysa Myers, a virus research engineer with McAfee. "They are taking it further. This one actually works on the older operating systems and not just Windows Vista beta."

The worm also changes every time it infects a file. While that makes it more difficult for primitive scanners to detect the malware, most modern anti-virus tools won't be fooled by this capability. A Microsoft spokesperson told vnunet.com that it is aware of the worm and stressed strethat the virus doesn't exploit any vulnerabilities in its software. "Microsoft recommends consumers do not accept files from un-trusted sources and should use up-to-date third-party anti-virus products," he added.