The security advisory -- a mechanism Microsoft uses to both alert users of impending threats and give them advice or workarounds to apply -- repeats recommendations that most security vendors have been offering since the worm debuted two weeks ago.
It also notes that infected PCs will be in danger on Friday, Feb. 3, when the worm will overwrite several popular file formats, including those of Microsoft Office, with useless data.
But according to the team in charge of Microsoft's Windows Software Removal Tool, that program won't be updated until after the Friday deadline passes.
"Microsoft releases a new version of the Windows Malicious Software Removal Tool every month on the second Tuesday of the month together with the other security updates," wrote developers on the group's blog. "The next version, targeted for release on February 14th, will detect and remove this worm."
The blog offered no explanation why the tool wouldn't be updated earlier, nor did Microsoft immediately respond to questions. Each month, Microsoft pushes a revised tool to Windows users who have Automatic Update enabled for Windows Update or Microsoft Update.
The Redmond, Wash.-based company has released the Malicious Software Removal Tool off-schedule once before, in August 2005, shortly after the Zotob worm began striking Windows 2000 systems.