Physical Security Dependencies

What it means

Physical security dependencies are facilities, power, environmental systems, devices, access controls, and supply conditions whose failure can undermine digital security and service continuity.

Why it matters

Architecture decisions determine where trust is granted, where controls can observe and act, and how failures propagate across systems and organizations.

Practical focus

• Identify assets, data flows, trust boundaries, and required outcomes
• Place controls where they can enforce or observe the intended behavior
• Document assumptions, dependencies, and failure modes
• Validate the design against realistic threats and operating constraints

Common mistakes

• Selecting products before defining requirements
• Assuming a diagram proves enforcement
• Ignoring inherited, legacy, or third-party dependencies
• Failing to test how the design behaves during degradation or attack

Certification relevance

This subject appears in or supports the following certification bodies of knowledge:

Authoritative sources

• NIST SP 800-53 Rev. 5 — Security and Privacy Controls
• CISA Cross-Sector Cybersecurity Performance Goals