The primary objective of physical access controls is to enforce the principle of least privilege in the physical domain. These controls are designed to manage and restrict entry to facilities, rooms, and specific areas to safeguard an organization's most critical assets. This includes protecting personnel, preventing unauthorized access to sensitive information stored on servers or in documents, and securing physical resources like equipment and infrastructure from theft, damage, or tampering. By limiting access to only authorized individuals, these controls form a foundational layer of a defense-in-depth security strategy, directly supporting the confidentiality, integrity, and availability of organizational assets.

A. Physical controls are meant to complement, not replace, technical security controls as part of a layered, defense-in-depth security posture.

B. This contradicts the security principle of least privilege, which dictates that access should be restricted based on job requirements, not granted universally.

D. Allowing public access to sensitive areas would introduce unacceptable risks, directly undermining the fundamental purpose of security controls.

1. National Institute of Standards and Technology (NIST). (2020). Security and Privacy Controls for Information Systems and Organizations (NIST Special Publication 800-53

Revision 5). U.S. Department of Commerce. The purpose of the Physical and Environmental Protection (PE) control family is to "limit physical access to systems

equipment

and the respective operating environments to authorized individuals." (p. 199

PE Family Introduction).

2. International Organization for Standardization. (2022). Information security

cybersecurity and privacy protection — Information security controls (ISO/IEC 27002:2022). The objective for control 7.2 "Physical entry" is to "ensure that only authorized personnel are allowed to enter secured areas." (Annex A

Control 7.2).

3. Saltzer

J. H.

& Schroeder

M. D. (1975). The Protection of Information in Computer Systems. Communications of the ACM

18(7)

387–408. This foundational paper on computer security design principles implicitly supports physical controls through the principle of "Complete Mediation

" where every access must be checked. Physical controls are the first layer of mediation for physical assets. (Section A.3

p. 5). https://doi.org/10.1145/361011.361062