- published: 04 Nov 2013
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The Morris worm or Internet worm of November 2, 1988 was one of the first computer worms distributed via the Internet. It is considered the first worm and was certainly the first to gain significant mainstream media attention. It also resulted in the first conviction in the US under the 1986 Computer Fraud and Abuse Act. It was written by a student at Cornell University, Robert Tappan Morris, and launched on November 2, 1988 from MIT.
According to its creator, the Morris worm was not written to cause damage, but to gauge the size of the Internet. However, the worm was released from MIT to disguise the fact that the worm originally came from Cornell. Additionally, the Morris worm worked by exploiting known vulnerabilities in Unix sendmail, finger, and rsh/rexec, as well as weak passwords. Due to reliance on rsh (normally disabled on untrusted networks) it should not succeed on a recent, properly configured system.
A supposedly unintended consequence of the code, however, caused it to be more damaging: a computer could be infected multiple times and each additional process would slow the machine down, eventually to the point of being unusable. This would have the same effect as a fork bomb and crash the computer. The main body of the worm could only infect DEC VAX machines running 4BSD, and Sun-3 systems. A portable C "grappling hook" component of the worm was used to pull over (download) the main body, and the grappling hook could run on other systems, loading them down and making them peripheral victims.