Nine out of every ten large corporations and government agencies have been attacked by computer intruders, to judge from the results of a survey conducted by the FBI and reported by the Associated Press in April 2002. Interestingly, the study found that only about one company in three reported or publicly acknowledged any attacks. That reticence to reveal their victimization makes sense. To avoid loss of customer confidence and to prevent further attacks by intruders who learn that a company may be vulnerable, most businesses do not publicly report computer security incidents.