SA-20 — Customized Development of Critical Components
Organizations determine that certain system components likely cannot be trusted due to specific threats to and vulnerabilities in those components for which there are no viable security controls to adequately mitigate risk. Reimplementation or custom development of such components may satisfy requirements for higher assurance and is carried out by initiating changes to system components (including hardware, software, and firmware) such that the standard attacks by adversaries are less likely to succeed. In situations where no alternative sourcing is available and organizations choose not to reimplement or custom develop critical system components, additional controls can be employed. Controls include enhanced auditing, restrictions on source code and system utility access, and protection from deletion of system and application files.
Read the official statement, discussion, parameters, enhancements, and assessment methods →
NIST CSF 2.0 informative references
These CSF Subcategories list this base control or one of its enhancements in the imported NIST informative reference.
NIST SP 800-171 and SP 800-172
SP 800-171 requirements sourcing this control
SP 800-172 enhanced requirements sourcing this control
MITRE D3FEND techniques
MITRE ATT&CK relationships
Curated mitigation mappings
Inferred behavior relationships
Experimental: These relationships are inferred through D3FEND and must be validated against architecture, telemetry, and threat context.
Use the map without overclaiming.
A CSF informative reference is not an equivalence statement. A source-control relationship is not proof of implementation. A D3FEND semantic relationship is not a product claim. An inferred ATT&CK link is a hypothesis for engineering analysis.
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST or MITRE. Informative references and cross-framework relationships support navigation and analysis; they do not establish compliance, applicability, equivalence, control inheritance, or guaranteed mitigation effectiveness.