Nimda (computer worm)

Nimda is a computer worm, isolated in September 2001. It is also a file infector. It quickly spread, 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. Due to the release date, some media quickly began speculating a link between the virus and Al Qaeda, though this relationship ended up being untrue.

Nimda affected both user workstations (clients) running Windows 95, 98, Me, NT, or 2000 and servers running Windows NT and 2000.

The worm's name spelled backwards is "admin".

Methods of infection

Nimda was so effective partially because it—unlike other famous 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. [http://seifried.org/lasg/introduction-to-security/] )
* via back doors left behind by the "Code Red II" and "sadmind/IIS" worms.

ee also

* Timeline of notable computer viruses and worms

External links

* [http://www.cert.org/advisories/CA-2001-26.html Cert advisory on Nimda]
* [http://www.f-secure.com/v-descs/nimda.shtml Antivirus vendor F-Secure's info on Nimda]