id: "SC-03(03)" title: "Minimize Nonsecurity Functionality" family: "SC" family_name: "System and Communications Protection" sort_id: "sc-03.03" priority: "P1" implementation_level: "system" parent: "SC-03" enhancement: True
Statement
Minimize the number of nonsecurity functions included within the isolation boundary containing security functions.
Guidance
Where it is not feasible to achieve strict isolation of nonsecurity functions from security functions, it is necessary to take actions to minimize nonsecurity-relevant functions within the security function boundary. Nonsecurity functions contained within the isolation boundary are considered security-relevant because errors or malicious code in the software can directly impact the security functions of systems. The fundamental design objective is that the specific portions of systems that provide information security are of minimal size and complexity. Minimizing the number of nonsecurity functions in the security-relevant system components allows designers and implementers to focus only on those functions which are necessary to provide the desired security capability (typically access enforcement). By minimizing the nonsecurity functions within the isolation boundaries, the amount of code that is trusted to enforce security policies is significantly reduced, thus contributing to understandability.
Assessment Objective
the number of non-security functions included within the isolation boundary containing security functions is minimized.
System and communications protection policy
procedures addressing security function isolation
system design documentation
system configuration settings and associated documentation
system audit records
system security plan
other relevant documents or records
System/network administrators
organizational personnel with information security responsibilities
Mechanisms supporting and/or implementing an isolation boundary