Because of the increased activity over the Internet, viruses and worms have become serious pests. As the Internet advances, these pests are becoming much more sophisticated. There capacity to spread across the Internet in just a matter of hours can cause serious floods of payloads to systems. One recent virus that caused, and still is causing, an up-roar across the Internet is the 'Nimda'.

What is Nimda? Nimda is a computer virus appearing first on September 18, 2001 when it caused massive delays by creating huge amounts of traffic as it spread across the Internet. Nimda has four main attach mechanisms: web server to web server (IIS 4 / 5), to desktops through an e-mail attachment called README.EXE or ADMIN.DLL; browsing infected Web sites from Windows desktop or server machines; and by shares across internal networks. Once an internal machine is infected, it is possible for the virus to spread to shared drives and machines.

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