Ultimately, people hack into computers. People delete files and alter system programs. People steal information. You should determine who you trust (and who you don’t trust).
Much of this book has been devoted to techniques that protect computer systems from attacks by outsiders. This focus isn’t our only preoccupation: overwhelmingly, companies fear attacks from outsiders more than they fear attacks from the inside. Unfortunately, such fears are often misplaced. Statistics compiled by the FBI and others show that the majority of major economic losses from computer crime appear to involve people on the “inside.”
Companies seem to fear attacks from outsiders more than insiders because they fear the unknown. Few managers want to believe that their employees would betray their bosses, or the company as a whole. Few businesses want to believe that their executives would sell themselves out to the competition. As a result, many organizations spend vast sums protecting themselves from external threats, but do little in the way of instituting controls and auditing to catch and prevent problems from the inside.
Not protecting your organization against its own employees is a short-sighted policy. Protecting against insiders automatically buys an organization considerable protection from outsiders as well. After all, what do outside attackers want most of all? They want an account on your computer, an account from which they can unobtrusively investigate ...