8th Dangerous Computer Virus- NIMDA

Nimda

Type	Multiple
Operating system(s) affected	Windows 95–XP

Nimda is a computer worm, and is also a file infector. It quickly spreads, eclipsing the economic damage caused by past outbreaks such as Code Red. Multiple propagation vectors allowed Nimda to become the Internet’s most widespread virus/worm within 22 minutes.
The worm was released on September 18, 2001.^[1] Due to the release date, exactly one week after the attacks on the World Trade Center and Pentagon, some media quickly began speculating a link between the virus and Al Qaeda, though this theory ended up proving unfounded.
Nimda affected both user workstations (clients) running Windows 95, 98, Me, NT, 2000 or XP and servers running Windows NT and 2000.
The worm's name origin comes from the reversed spelling of it, which is "admin".
F-Secure found the text^[2] "Concept Virus(CV) V.5, Copyright(C)2001 R.P.China" in the Nimda code.

Contents 1 Methods of infection 2 See also 3 References 4 External links

Methods of infection

Nimda was so effective partially because it—unlike other infamous malware like the Morris worm or Code Red—uses five different infection vectors:

• via email
• via open network shares
• via browsing of compromised web sites
• exploitation of various Microsoft IIS 4.0 / 5.0 directory traversal vulnerabilities. (Both Code Red, and Nimda were hugely successful exploiting well known and long solved vulnerabilities in the Microsoft IIS server.^[3])
• via back doors left behind by the "Code Red II" and "sadmind/IIS" worms.