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3.4.5Restrict who can change what

Access to make changes is defined, documented, approved, and enforced.

The requirement, verbatim

NIST SP 800-171 Rev. 2 · 3.4.5

Define, document, approve, and enforce physical and logical access restrictions associated with changes to organizational systems.

Requirement 3.4.5, practice name in the CMMC assessment guide: Access Restrictions for Change.

NIST's discussion

Any changes to the hardware, software, or firmware components of systems can potentially have significant effects on the overall security of the systems. Therefore, organizations permit only qualified and authorized individuals to access systems for purposes of initiating changes, including upgrades and modifications. Access restrictions for change also include software libraries. Access restrictions include physical and logical access control requirements, workflow automation, media libraries, abstract layers (e.g., changes implemented into external interfaces rather than directly into systems), and change windows (e.g., changes occur only during certain specified times). In addition to security concerns, commonly-accepted due diligence for configuration management includes access restrictions as an essential part in ensuring the ability to effectively manage the configuration.

NIST SP 800-128 provides guidance on configuration change control.

NIST SP 800-171 Rev. 2, discussion under 3.4.5. Whitespace normalised; wording unchanged.

Assessment objectives

An assessor decides each of these separately. The requirement is met only when every objective is.

  1. [a] physical access restrictions associated with changes to the system are defined
  2. [b] physical access restrictions associated with changes to the system are documented
  3. [c] physical access restrictions associated with changes to the system are approved
  4. [d] physical access restrictions associated with changes to the system are enforced
  5. [e] logical access restrictions associated with changes to the system are defined
  6. [f] logical access restrictions associated with changes to the system are documented
  7. [g] logical access restrictions associated with changes to the system are approved
  8. [h] logical access restrictions associated with changes to the system are enforced

NIST SP 800-171A, determination statements for 3.4.5.

For assessors: examine, interview, test

NIST SP 800-171A names what an assessor may examine, whom they may interview, and what they may test for this requirement. Assessors select from these lists; they are not a checklist of everything you must produce.

Examine
  • Configuration management policy
  • configuration management plan
  • procedures addressing access restrictions for changes to the system
  • system design documentation
  • system architecture and configuration documentation
  • system security plan
  • system configuration settings and associated documentation
  • logical access approvals
  • physical access approvals
  • access credentials
  • change control records
  • system audit logs and records
  • other relevant documents or records
Interview
  • Personnel with logical access control responsibilities
  • personnel with physical access control responsibilities
  • personnel with information security responsibilities
  • system or network administrators
Test
  • Mechanisms implementing access restrictions for changes to the system

NIST SP 800-171A, potential assessment methods and objects for 3.4.5.

Evidence

No evidence examples are published for this requirement yet. The objectives above are what an assessor checks; evidence is whatever shows each one is true in your environment, dated and kept with your system security plan.

Scoring weight

Worth 5 points. Not meeting this requirement subtracts 5 from your 110-point SPRS score. These are the requirements with the largest effect on your posture.

DoD NIST SP 800-171 Assessment Methodology v1.2.1 weighting, as carried in the Bedrock scoring table. The score starts at 110 and subtracts the weight of every requirement not met.

In Rev. 3

Rev. 2 is what your contract requires today. A standing DoD class deviation keeps Rev. 2 in force; NIST has published Rev. 3, but it is not adopted for contracts. In Rev. 3 this requirement is no significant change: 03.04.05 Access Restrictions for Change.

See the Rev. 2 and Rev. 3 wording word by word, or start with the status page.

Where this page's facts come from
Requirement text
bedrock-cmmc-api@89b8e8e:migrations/004_reference_requirements.sql#Requirement.basicRequirement@rev2
Discussion
bedrock-cmmc-api@89b8e8e:migrations/004_reference_requirements.sql#Requirement.discussion@rev2
Practice name
bedrock-cmmc-api@89b8e8e:migrations/004_reference_requirements.sql#Requirement.title@rev2 (CMMC Assessment Guide practice name)
Objectives
bedrock-cmmc-api@89b8e8e:migrations/005_reference_objectives.sql#AssessmentObjective.description@rev2
Examine, interview, test
bedrock-cmmc-api@89b8e8e:migrations/005_reference_objectives.sql#AssessmentObjective.description@rev2 ({examineGuidance, interviewGuidance, testGuidance})
Level
bedrock-cmmc-api@89b8e8e:migrations/021_fix_level1_requirements.sql#Requirement.cmmcLevel@rev2
Weight
bedrock-cmmc-api@89b8e8e:internal/cmmc/requirement_values.go#requirementValues (DoD AM v1.2.1 / eMASS L2 template v3.8)
Rev. 3 mapping
bedrock-cmmc-api@89b8e8e:docs/reference/nist-800-171-rev3/normalized/r2_r3_transition_map.json#r2_to_r3
Plain-language title and summary
editorial/CMMC Navigator.dc.html#RAW (Foxx Cyber editorial)