| name | SA-20_customized-development-of-critical-components |
| description | Reimplement or custom develop the following critical system components: [organization-defined]. |
| category | configuration |
| version | 5.2.0 |
| author | cyberstrike-official |
| tags | ["nist","sp800-53","rev5","sa-20","sa"] |
| tech_stack | ["any"] |
| cwe_ids | ["CWE-16"] |
| chains_with | ["CP-2","RA-9","SA-8"] |
| prerequisites | [] |
| severity_boost | {"CP-2":"Chain with CP-2 for comprehensive security coverage","RA-9":"Chain with RA-9 for comprehensive security coverage","SA-8":"Chain with SA-8 for comprehensive security coverage"} |
SA-20 Customized Development of Critical Components
High-Level Description
Family: System and Services Acquisition (SA)
Framework: NIST SP 800-53 Rev 5
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.
What to Check
How to Test
Step 1: Review Documentation
Examine the System Security Plan (SSP) and related artifacts for SA-20 implementation details. Verify the organization has documented how this control is satisfied.
Step 2: Validate Implementation
# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly
# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null
Step 3: Test Operating Effectiveness
Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.
Tools
| Tool | Purpose | Usage |
|---|
| Manual Review | Documentation and interview-based | N/A |
Remediation Guide
Control Statement
Reimplement or custom develop the following critical system components: [organization-defined].
Implementation Guidance
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.
