Most of these threats come from insiders bent on revenge or from outsiders joy-riding via telephone. An incident in November of 1987 made national headlines when a 99-line worm infected 6,200 computers via an electronic mail service provided by Internet. This incident apparently began playfully, but had devastating effects, causing an estimated $96 million in disruption and repair time. While most States and the Federal Government have passed specific computer-crime legislation, prosecution can be cumbersome and expensive, and certain types of intrusions may not be covered. As a result of the November incident, a bill, the Computer Virus Eradication Act of 1988, has been introduced to define the introduction or conscious dissemination of viruses or other harmful programs affecting inter-State or foreign commerce as malicious mischief. In addition, to complement security policies and procedures, some organizations are using computer programs that combat or detect viruses. A glossary and a list of 8 preventive measures are included.