Security requirement
- a.Implement non-persistent [Organization-defined: non-persistent system components and services].
- b.Initiate non-persistent [Organization-defined: non-persistent system components and services] from a known state.
- c.Terminate non-persistent [Organization-defined: SELECTED PARAMETER VALUE(S)] [Organization-defined: non-persistent system components and services].
Discussion
Implementation of non-persistent components and services mitigates risk from advanced persistent threats (APTs) by reducing the targeting capability of adversaries (i.e., window of opportunity and available attack surface) to initiate and complete attacks. By implementing the concept of non-persistence for selected system components and services, organizations can provide a trusted computing resource for a specific time period that does not give adversaries sufficient time to exploit vulnerabilities in their systems and operating environments. The use of non-persistent components and services mitigates risk by limiting the targeting capability of adversaries (i.e., reducing the window of opportunity and available attack surface) to initiate and complete attacks. Non-persistent system components and services are activated as required from a known (trusted) state and terminated periodically or at the end of sessions. The use of non-persistent system components and services also increases the work factor of adversaries.
Non-persistence can be achieved by refreshing system components, periodically reimaging components, or using a variety of common virtualization techniques. Non-persistent services can be implemented by using virtual machines or as new instances of processes on physical machines (persistent or non-persistent). The benefit of periodic refreshes of system components and services is that it does not require organizations to determine in advance whether compromises have occurred, which may be difficult or impossible. The refresh of selected system components and services occurs with sufficient frequency to prevent the spread or intended impact of attacks but not with such frequency that it makes the system unstable. This requirement does not enhance a specific requirement in SP 800-171 but can be used to strengthen the protection of CUI associated with critical programs or high value assets.
Tailoring decisions required
Resolve these values through the governing organization’s approved tailoring and risk-management process before declaring the requirement implemented.
Protection strategies supported
These classifications are carried from the official SP 800-172 OSCAL record and help explain the enhanced requirement’s defensive purpose.
Implementation perspective
Treat Non-Persistent System Components and Services as an enhanced CUI protection outcome for elevated threat conditions that must be reflected in the system boundary, documented implementation, operational behavior, and assessment evidence. Pay particular attention to flaw remediation, malicious-code protection, monitoring, integrity, and trustworthy handling of CUI.
- Confirm the federal agency selected this enhanced requirement for the critical program or high-value asset and identify the CUI system components, services, users, and external connections in scope.
- Resolve every organization-defined parameter through an approved governance and tailoring process.
- Map each clause of the requirement to an accountable owner, implementation mechanism, and evidence source.
- Verify that inherited and shared implementations are supported by current provider evidence and responsibility boundaries.
- Collect evidence during normal operation and review changes, exceptions, and deficiencies on a risk-based cadence.
Questions to ask
- Which critical-program or high-value-asset CUI, data flows, users, and services are protected by this enhanced requirement?
- Which portions are implemented locally, inherited, shared, or not applicable, and what evidence supports that determination?
- Do the system security plan, deployed configuration, operating process, and assessment evidence tell the same story?
- What change, incident, or threshold should trigger reassessment?
Evidence and validation
- patch and remediation records
- malware protection configuration
- monitoring alerts and response records
- integrity validation and exception reports
Common failure patterns
- patch compliance hiding unsupported assets
- alerts generated without response ownership
- exceptions that never expire
- integrity monitoring excluding critical configurations
Assessment objectives and methods
Assessment objectives (3)
- a.
[Organization-defined: non-persistent system components and services] are implemented.
- b.
[Organization-defined: non-persistent system components and services] are initiated from a known state.
- c.
[Organization-defined: non-persistent system components and services] are terminated [Organization-defined: SELECTED PARAMETER VALUE(S)].
Examine
- System and information integrity policy
- system and information integrity procedures
- system design documentation
- procedures addressing non-persistence for system components
- system security plan
- system configuration settings and associated documentation
- system audit records
- other relevant documents or records
Interview
- Personnel responsible for non-persistence
- personnel with information security responsibilities
- system/network administrators
- system developers
Test
- Automated mechanisms supporting and/or implementing the initiation and termination of non-persistent components
Source NIST SP 800-53 controls
These controls are referenced by the official SP 800-172 Rev. 3 OSCAL record. Open the corresponding control pages for complete control text, enhancements, D3FEND mappings, and related learning.
Authoritative sources
- NIST SP 800-172 Revision 3 official publication ↗
- NIST SP 800-172A Revision 3 official publication ↗
- NIST OSCAL Content release used for this import ↗
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. The official publications, the responsible federal agency, and the governing contract or agreement determine applicability, tailoring, assessment depth, and required implementation.