The Morris Worm: The First Significant Cyber Attack

By Kim Smiley

In 1988 the world was introduced to the concept of a software worm when the Morris worm made headlines for significantly disrupting the fledgling internet.  The mess left in the wake of the Morris worm took several days to clean up. The estimates for the cost of the Morris worm vary greatly from $100,000–10,000,000, but even at the lower range the numbers are still substantial.

A Cause Map, or visual root cause analysis, can be used to analyze this issue.  A Cause Map is built by asking “why” questions and using the answers to visually lay out the causes that contributed to an issue to show the cause-and-effect relationships.  In this example, a programmer was trying to build a “harmless” worm that could be used to gauge the size of the internet, but he made a mistake.  The goal was to infect each computer one time, but the worm was designed to duplicate itself every seventh time a computer indicated it already had the worm to make the worm hard to defend against.  The problem was that the speed of propagation was underestimated. Once released, the worm quickly reinfected computers over and over again until they were unable to function and the internet came crashing down.  (To view a Cause Map of this example, click on “View PDF” above.)

One of the lasting impacts from the Morris worm that is hard to quantify is the impact on cyber security.  The worm exploited known bugs that no one had worried about enough to fix.  At the time of the Morris worm, there was no commercial traffic on the internet or even Web sites.  The people who had access to the internet were a small, elite group and concerns about cyber security hadn’t really come up.  If the first “hacker” attack had had malicious intent behind it and came a little later it’s likely that the damage would have been much more severe.  While the initial impacts of the Morris worm were all negative, it’s a positive thing that it highlighted the need to consider cyber security relatively early in the development of the internet.

It’s also interesting to note that the programmer behind the Morris worm, Robert Tappan Morris, become the first person to be indicted under the 1986 Computer Fraud and Abuse Act. He was sentenced with a $10,050 fine, 400 hours of community service, and a three-year probation. Morris was a 23 year old graduate student at the time he released his infamous worm.  After this initial hiccup, Morris went one to have a successful career and now works in the MIT Computer Science and Artificial Intelligence Laboratory.