"The Federal Bureau of Investigation and private sector
security experts Tuesday warned of a sophisticated new virus dubbed
Nimda, which spreads both as a worm exploiting the same
vulnerabilities used by the recent Code Red and sadmind/IIS worms,
and as an e-mail virus. Experts said the worm could proliferate as
widely as Code Red.
The Computer Emergency Response Team Coordination Center
(CERT/CC), based at Carnegie-Mellon University, said "User machines
that are infected by this virus might see an increase in scanning
as the virus tries to compromise IIS servers. Many sites are
experiencing high loads of e-mail and network traffic as a result
of this activity."
London-based GFI Security Labs said Tuesday afternoon that Nimda
replicates quickly and has the ability to spread through e-mail
clients even if recipients don't open the attachment, ReadMe.exe,
which comes with infected e-mails."