3.1.6 Architecture Considerations

Architecture considerations involve balancing security controls with functionality, cost, and system performance to ensure resources remain accessible and resilient against failure.

Availability and Resilience Availability ensures that authorized users have timely and reliable access to data and resources. To maintain a resilient architecture, security professionals must implement strategies that prevent single points of failure. - Redundancy: Implementing duplicate components, such as power supplies or internet connections, to ensure service continues during a failure. - Backups: Maintaining copies of data to restore functionality after a corruption or loss event. - Failover: Automated switching to a standby system when the primary system fails. - Business Continuity: High-level planning that ensures the organization can continue operating during a disaster.

Scalability and Elasticity Architecture must be designed to handle fluctuating workloads while maintaining a strong security posture. - Scalability: The measurement of a system’s ability to handle increased load by adding resources (vertical or horizontal scaling). - Elasticity: Primarily a cloud concept, this is the ability of a system to automatically expand or contract resource allocation based on real-time demand. - Provisioning/Deprovisioning: The process of allocating and removing resources. Poor deprovisioning can lead to "zombie" assets that create security gaps.

Cost and Asset Value Security decisions are often driven by quantitative risk assessments and the financial impact of downtime. - Asset Value (AV): The total monetary worth of an asset, including replacement cost, repair cost, and the revenue it generates. - Replacement vs. Repair: Architecture planning must weigh the cost of fixing a component against the cost of a full replacement, including depreciation. - Indirect Costs: When an asset like a server fails, the cost is not just the hardware ($5,000) but the lost revenue (e.g., $3,000/day) during the lead time for shipping and installation. - ROI of Controls: Organizations should avoid implementing security controls that cost more than the asset they are protecting.

Risk Management Strategies Architectural choices are influenced by how the organization decides to handle specific threats. - Mitigation: Reducing the likelihood or impact of a risk through technical controls (e.g., installing an IPS). - Transference: Shifting the financial burden of a risk to a third party, such as purchasing cyber insurance or utilizing a cloud provider. - Acceptance: Acknowledging a risk exists but deciding that the cost of mitigation outweighs the potential loss.

Exam tips - Availability is the bridge between security and functionality; a perfect system is useless if it is inaccessible. - Redundancy is the primary method for eliminating single points of failure. - When calculating Asset Value, always include the "lost opportunity" or revenue generated by that asset. - Risk Mitigation aims to reduce risk to an "acceptable level" rather than zero.