Security requirement
Employ a diverse set of information technologies for the following system components in the implementation of the system: [Organization-defined: system components].
Discussion
Increasing the diversity of information technologies within organizational systems reduces the impact of exploitations or compromises of specific technologies. Such diversity protects against common mode failures, including those failures induced by supply chain attacks. Diversity in information technologies also reduces the likelihood that the means adversaries use to compromise one system component will be effective against other system components, thus further increasing the adversary work factor to successfully complete planned attacks. An increase in diversity may add complexity and management overhead that could ultimately lead to mistakes and unauthorized configurations. 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 Heterogeneity 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 secure architecture, boundary protection, communications security, cryptography, and isolation of CUI processing.
- 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
- network and trust-boundary diagrams
- firewall and gateway configurations
- cryptographic configuration and key records
- segmentation and isolation test results
Common failure patterns
- diagrams omitting cloud and third-party paths
- encryption enabled without key governance
- flat trust zones permitting unnecessary lateral movement
- boundary rules accumulating without owner review
Assessment objectives and methods
Assessment objectives (1)
a diverse set of information technologies is employed for [Organization-defined: system components] in the implementation of the system.
Examine
- System and communications protection policy
- system design documentation
- system configuration settings and associated documentation
- list of technologies deployed in the system
- acquisition documentation
- acquisition contracts for system components or services
- system security plan
- other relevant documents or records
Interview
- System/network administrators
- personnel with information security responsibilities
- personnel with system acquisition, development, and implementation responsibilities
Test
- Mechanisms supporting and/or implementing the use of a diverse set of information technologies
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.