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

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infrastructure, based on Service Organization Control (SOC) reports. See Chapter 15 for details on SOC reports.

      For all acquisitions, establish minimum security requirements. These should be modeled after your existing security policy. The security requirements for new hardware, software, or services should always meet or exceed the security of your existing infrastructure. When working with an external service, be sure to review any service-level agreement (SLA) to ensure that security is a prescribed component of the contracted services. When that external provider is crafting software or providing a service (such as a cloud provider), then a service-level requirement (SLR) may need to be defined. An SLR is a statement of the expectations of service and performance from the product or service of a vendor. Often, an SLR is provided by the customer/client prior to the establishment of the SLA (which should incorporate the elements of the SLR if the vendor expects the customer to sign the agreement).

      Two additional examples of organizational processes that are essential to strong security governance are change control/change management (see Chapter 16, “Managing Security Operations”) and data classification (see Chapter 5, “Protecting Security of Assets”).

      Organizational Roles and Responsibilities

      The following are the common security roles present in a typical secured environment:

       Senior Manager The organizational owner (senior manager) role is assigned to the person who is ultimately responsible for the security maintained by an organization and who should be most concerned about the protection of its assets. The senior manager must sign off on all security policy issues. There is no effective security policy if the senior management does not authorize and support it. The senior manager is the person who will be held liable for the overall success or failure of a security solution and is responsible for exercising due diligence and due care in establishing security for an organization. Even though senior managers are ultimately responsible for security, they rarely implement security solutions. In most cases, that responsibility is delegated to security professionals within the organization.

       Security Professional The security professional, information security (InfoSec) officer, or computer incident response team (CIRT) role is assigned to a trained and experienced network, systems, and security engineer who is responsible for following the directives mandated by senior management. The security professional has the functional responsibility for security, including writing the security policy and implementing it. The role of security professional may be labeled as an IS/IT role, but its focus is on protection more than function. The security professional role is often filled by a team that is responsible for designing and implementing security solutions based on the approved security policy. Security professionals are not decision makers; they are implementers. All decisions must be left to the senior manager.

       Asset Owner The asset owner role is assigned to the person who is responsible for classifying information for placement and protection within the security solution. The asset owner is typically a high-level manager who is ultimately responsible for asset protection. However, the asset owner usually delegates the responsibility of the actual data management tasks to a custodian.

       Custodian The custodian role is assigned to the user who is responsible for the tasks of implementing the prescribed protection defined by the security policy and senior management. The custodian performs all activities necessary to provide adequate protection for the CIA Triad (confidentiality, integrity, and availability) of data and to fulfill the requirements and responsibilities delegated from upper management. These activities can include performing and testing backups, validating data integrity, deploying security solutions, and managing data storage based on classification.

       User The user (end user or operator) role is assigned to any person who has access to the secured system. A user's access is tied to their work tasks and is limited so that they have only enough access to perform the tasks necessary for their job position (the principle of least privilege). Users are responsible for understanding and upholding the security policy of an organization by following prescribed operational procedures and operating within defined security parameters.

       Auditor An auditor is responsible for reviewing and verifying that the security policy is properly implemented and the derived security solutions are adequate. The auditor produces compliance and effectiveness reports that are reviewed by the senior manager. Issues discovered through these reports are transformed into new directives assigned by the senior manager to security professionals or custodians.

      All of these roles serve an important function within a secured environment. They are useful for identifying liability and responsibility as well as for identifying the hierarchical management and delegation scheme.

      Security Control Frameworks

      One of the first and most important security planning steps is to consider the overall security control framework or structure of the security solution desired by the organization. You can choose from several options in regard to security concept infrastructure; however, one of the more widely used security control frameworks is Control Objectives for Information and Related Technology (COBIT). COBIT is a documented set of best IT security practices crafted by the Information Systems Audit and Control Association (ISACA). It prescribes goals and requirements for security controls and encourages the mapping of IT security ideals to business objectives. COBIT is based on six key principles for governance and management of enterprise IT:

       Provide Stakeholder Value

       Holistic Approach

       Dynamic Governance System

       Governance Distinct from Management

       Tailored to Enterprise Needs

       End-to-End Governance System

      COBIT is used not only to plan the IT security of an organization but also as a guideline for auditors. COBIT is a widely recognized and respected security control framework.

      Fortunately, COBIT is only modestly referenced on the exam, so further details are not necessary. However, if you have interest in this concept, please visit the ISACA website (www.isaca.org/cobit), or if you want a general overview, read the COBIT entry on Wikipedia.

      There are many other standards and guidelines for IT security. Here are a few:

       NIST 800-53 Rev. 5, “Security and Privacy Controls for Information Systems and Organizations” (csrc.nist.gov/publications/detail/sp/800-53/rev-5/final), contains U.S. government–sourced general recommendations for organizational security.

       The Center for Internet Security (CIS) provides OS, application, and hardware security configuration guides at www.cisecurity.org/cis-benchmarks.

       NIST Risk Management Framework (RMF) (csrc.nist.gov/projects/risk-management/rmf-overview) establishes mandatory requirements for federal agencies. The

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