Robert Tappan Morris

Robert Tappan Morris (born 1965) is an associate professor at Massachusetts Institute of Technology. He is best known for creating the Morris Worm in 1988, considered the first computer worm on the Internet. He is the son of Robert Morris, the former chief scientist at the National Computer Security Center, a division of the National Security Agency (NSA).

The worm

Main article: Morris Worm

Morris created the worm while he was a graduate student at Cornell University. The original intent, according to him, was to gauge the size of the Internet. He released the worm from the Massachusetts Institute of Technology (MIT) to conceal the fact that it actually originated from Cornell. Unknown to Morris, the worm had a design flaw. The worm was programmed to check each computer it found to determine if the infection was already present. However, Morris believed that some administrators might try to defeat his worm by instructing the computer to report a false positive. To compensate for this possibility, Morris directed the worm to copy itself anyway, fourteen percent of the time, no matter the response to the infection-status interrogation. This level of replication proved excessive and the worm spread rapidly, infecting several thousand computers. It was estimated that the cost of repair for the damage caused by the worm at each system ranged from $200 to more than $53,000. The worm exploited several vulnerabilities to gain entry to targeted systems, including:

* a hole in the debug mode of the Unix sendmail program,

* a buffer overrun hole in the fingerd network service,

* the transitive trust enabled by people setting up rexec/rsh network logins without password requirements.

Above retrieved from Answers.com

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