Any system you build, including a security system, must have benefits that outweigh the costs. This tip, excerpted from Intrusion Detection, by Rebecca Gurley Bace, published by New Riders, discusses the costs and benefits of an intrusion-detection system.
In building a cost benefit model, be absolutely certain to include the following items:
- The ROI associated with protecting the corporate reputation. For instance, what is the business impact of hackers taking over the corporate Web site, substituting pornographic images for corporate logos, and posting text full of racial slurs and slanderous remarks about the firm's largest customer?
- The ROI associated with keeping the corporate stockholders happy. For instance, what is the stock price impact of a succession of security incidents, all publicized on the front page of a major newspaper?
- The ROI associated with maintaining continuity of system service. Here's a test question: What is the business impact of a denial-of-service attack that takes all of your systems down for a day? A week? Longer?
Risk assessment provides critical input to your security strategy: a rough idea of what information security is worth to the organization.