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A self-replicating program which shares
many characteristics of a virus. Worms have become a serious problem
in recent years, as crackers and script kiddies seek new ways
to disrupt computers on the internet. Unlike viruses, which generally need a
host of some kind such as a word-processing document or an executable
program file to reproduce themselves, worms can copy themselves from one
computer to the next almost invisibly. Many modern worms have exploited
vulnerabilities in popular server software created by Microsoft.
Their danger lies in their ability to do this extremely quickly; the sql
Slammer worm, which was released in early 2003, flooded thousands of web
server with data within minutes of its release, forcing many companies and
organisations to shut down their networks. Other recent examples
include Code Red, which caused similarly widespread chaos in 2001.
The
most famous worm in the internet's history was created by Robert Morris, a
computer science graduate at Cornell University, in 1988. Although his
program was intended to be completely benign, an unfortunate coding error
caused it to become destructive and it eventually caused 6,000 machines to
crash, at that time about 10% of all the computers on the internet. |
