Hackers have been fond not only of intruding into networks; they also contributed to the creation of the first Internet worms. The concept of a worm is a bit different from that of classic hacking, but it goes back to the same principles: instead of getting into a network themselves, they send a small program they have coded to do the job. It is from this concept that Robert Tappan Morris, today a professor at the Massachusetts Institute of Technology (MIT), created the first Internet worm.

Once again, it was curiosity that drove Morris to create this worm. According to him, the main purpose of this program was to probe the Internet to estimate its size, that is, know the number of computers connected. At that time the Internet only connected a few machines, and the scope did not seem daunting for this little piece of code. However, Morris neglected a parameter when creating his worm, causing a lot more damage than he had anticipated.

A More Dangerous Worm than Initially Foreseen

The Morris worm, which was sent from computers at MIT, was programmed to probe a computer and copy itself into the system if the machine was not already infected. The problem started when he imagined some system administrators might have the idea of circumventing the menace of this worm, by making it believe the machine was already infected when in fact it was not. Therefore, he modified his code to force a copy to be stored each time the worm accessed a computer, regardless of its infection status.

This caused the worm to spread like wildfire, infecting several thousand machines in a few hours. It was estimated that fixing each infected system cost between $200 and $53,000, depending on the machine. The worm mobilized different programmer teams to stop it, and it took several days for the attack to be neutralized.

Robert Tappan Morris was found guilty of computer fraud, and was sentenced to three years' probation, 400 hours of community service and a fine of $10,050.