Читать книгу (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide - Mike Chapple - Страница 31

We often hear how important security is, but we don't always understand why. Security is important because it helps to ensure that an organization is able to continue to exist and operate in spite of any attempts to steal its data or compromise its physical or logical elements. Security should be viewed as an element of business management rather than an IT concern. In fact, IT and security are different. Information technology (IT) or even information systems (IS) is the hardware and software that support the operations or functions of a business. Security is the business management tool that ensures the reliable and protected operation of IT/IS. Security exists to support the objectives, mission, and goals of the organization.

Generally, a security framework should be adopted that provides a starting point for how to implement security. Once an initiation of security has been accomplished, then fine-tuning that security is accomplished through evaluation. There are three common types of security evaluation: risk assessment, vulnerability assessment, and penetration testing (these are covered in detail in Chapter 2 and Chapter 15, “Security Assessment and Testing”). Risk assessment is a process of identifying assets, threats, and vulnerabilities, and then using that information to calculate risk. Once risk is understood, it is used to guide the improvement of the existing security infrastructure. Vulnerability assessment uses automated tools to locate known security weaknesses, which can be addressed by adding in more defenses or adjusting the existing protections. Penetration testing uses trusted individuals to stress-test the security infrastructure to find issues that may not be discovered by the prior two means, with the goal of finding those concerns before an adversary takes advantage of them.

Security should be cost-effective. Organizations do not have infinite budgets and thus must allocate their funds appropriately. Additionally, an organizational budget includes a percentage of monies dedicated to security, just as most other business tasks and processes require capital, not to mention payments to employees, insurance, retirement, and so on. You should select security controls that provide the greatest protection for the lowest resource cost.

Security should be legally defensible. The laws of your jurisdiction are the backstop of organizational security. When someone intrudes into your environment and breaches security, especially when such activities are illegal, then prosecution in court may be the only available response for compensation or closure. Also, many decisions made by an organization will have legal liability issues. If required to defend a security action in the courtroom, legally supported security will go a long way toward protecting your organization from facing large fines, penalties, or charges of negligence.

Security is a journey, not a finish line. It is not a process that will ever be concluded. It is not possible to fully secure something, because security issues are always changing. Our deployed technology is changing by the passage of time, by the users, and by the adversaries discovering flaws and developing exploits. The defenses that were sufficient yesterday may not be sufficient tomorrow. As new vulnerabilities are discovered, as new means of attack are crafted and new exploits are built, we have to respond by reassessing our security infrastructure and responding appropriately.