The Nimda worm uses an existing backdoor (Unicode exploit) to gain access to a system to install itself. Once someone has access to root.exe, they could do anything wanted on an unpatched, compromised host. Once a system is properly patched, Nimda and other worms will not be able to use that entry point.
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.