Merry christma: an early network worm

A computer worm disguised as a benign holiday greeting spread rapidly via email and clogged up networks worldwide. The story is all too common today, but this happened to corporate and university mainframes in 1987, in the infancy of the computer virus problem, even before the famous Internet, or Morris, worm. This article reviews 1987's relevant global networking environment, the way the Christma worm spread, the events surrounding its worldwide propagation, and the surprising effect it had once it got inside IBM.