Experts say the Nimda virus spreads through e-mail, vulnerable servers, and the Internet via open network sharing features and altered Web pages.

Antivirus experts and authorities spent Tuesday tracking the fast spread of a new computer worm that may not require user action to propagate itself, and so may surpass the infection rate of the damaging Code Red virus released earlier this year. Called the Win32.Nimda.A@mm virus, or "Nimda" by security experts, the virus discovered Tuesday can spread through e-mail, vulnerable Internet Information Servers (IIS) and the Internet using open network sharing features and altered Web pages. Officials say the virus is spreading fast worldwide and while it does not currently deliver a damaging payload, it is already slowing networks and systems connected to the Web, including e-mail. Experts say the virus can spread via e-mail like the Loveletter and Anna Kournikova viruses and through servers like Code Red and Code Blue. It uses Internet file-sharing features to propagate. Symantec Security Response senior director Sharon Ruckman, whose antivirus company rated Nimda a category 4 out of 5 threat, told NewsFactor experts are concerned at the "triple threat" posed by the worm.