SA-8(23)_secure-defaults

SA-8(23) Secure Defaults

Enhancement of: SA-8

High-Level Description

Family: System and Services Acquisition (SA) Framework: NIST SP 800-53 Rev 5

The principle of secure defaults states that the default configuration of a system (including its constituent subsystems, components, and mechanisms) reflects a restrictive and conservative enforcement of security policy. The principle of secure defaults applies to the initial (i.e., default) configuration of a system as well as to the security engineering and design of access control and other security functions that follow a "deny unless explicitly authorized" strategy. The initial configuration aspect of this principle requires that any "as shipped" configuration of a system, subsystem, or system component does not aid in the violation of the security policy and can prevent the system from operating in the default configuration for those cases where the security policy itself requires configuration by the operational user.

Restrictive defaults mean that the system will operate "as-shipped" with adequate self-protection and be able to prevent security breaches before the intended security policy and system configuration is established. In cases where the protection provided by the "as-shipped" product is inadequate, stakeholders assess the risk of using it prior to establishing a secure initial state. Adherence to the principle of secure defaults guarantees that a system is established in a secure state upon successfully completing initialization. In situations where the system fails to complete initialization, either it will perform a requested operation using secure defaults or it will not perform the operation. Refer to the principles of continuous protection and secure failure and recovery that parallel this principle to provide the ability to detect and recover from failure.

The security engineering approach to this principle states that security mechanisms deny requests unless the request is found to be well-formed and consistent with the security policy. The insecure alternative is to allow a request unless it is shown to be inconsistent with the policy. In a large system, the conditions that are satisfied to grant a request that is denied by default are often far more compact and complete than those that would need to be checked in order to deny a request that is granted by default.

What to Check

• Verify SA-8(23) Secure Defaults is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for SA-8(23)
• Verify enhancement builds upon base control SA-8

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SA-8(23) 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

Remediation Guide

Control Statement

Implement the security design principle of secure defaults in [organization-defined].

Implementation Guidance

The principle of secure defaults states that the default configuration of a system (including its constituent subsystems, components, and mechanisms) reflects a restrictive and conservative enforcement of security policy. The principle of secure defaults applies to the initial (i.e., default) configuration of a system as well as to the security engineering and design of access control and other security functions that follow a "deny unless explicitly authorized" strategy. The initial configuration aspect of this principle requires that any "as shipped" configuration of a system, subsystem, or system component does not aid in the violation of the security policy and can prevent the system from operating in the default configuration for those cases where the security policy itself requires configuration by the operational user.

Restrictive defaults mean that the system will operate "as-shipped" with adequate self-protection and be able to prevent security breaches before the intended security policy and system configuration is established. In cases where the protection provided by the "as-shipped" product is inadequate, stakeholders assess the risk of using it prior to establishing a secure initial state. Adherence to the principle of secure defaults guarantees that a system is established in a secure state upon successfully completing initialization. In situations where the system fails to complete initialization, either it will perform a requested operation using secure defaults or it will not perform the operation. Refer to the principles of continuous protection and secure failure and recovery that parallel this principle to provide the ability to detect and recover from failure.

The security engineering approach to this principle states that security mechanisms deny requests unless the request is found to be well-formed and consistent with the security policy. The insecure alternative is to allow a request unless it is shown to be inconsistent with the policy. In a large system, the conditions that are satisfied to grant a request that is denied by default are often far more compact and complete than those that would need to be checked in order to deny a request that is granted by default.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - SA-8(23)
• NIST SP 800-53A Rev 5 (Assessment Procedures)
• NIST SP 800-53 Rev 5 Full Catalog

Checklist

• Control documented in SSP
• Implementation evidence collected
• Operating effectiveness validated
• Continuous monitoring in place
• Related controls (CM-2, CM-6, SA-4) reviewed