3.1.5Give people the least access they need

Admin rights only where the job requires them, and only for as long as it requires them.

AC
Level 2
3 pt
Rev. 3: Reworded

The requirement, verbatim

NIST SP 800-171 Rev. 2 · 3.1.5
Employ the principle of least privilege, including for specific security functions and privileged accounts.

Requirement 3.1.5, practice name in the CMMC assessment guide: Least Privilege.

NIST's discussion

Organizations employ the principle of least privilege for specific duties and authorized accesses for users and processes. The principle of least privilege is applied with the goal of authorized privileges no higher than necessary to accomplish required organizational missions or business functions. Organizations consider the creation of additional processes, roles, and system accounts as necessary, to achieve least privilege. Organizations also apply least privilege to the development, implementation, and operation of organizational systems. Security functions include establishing system accounts, setting events to be logged, setting intrusion detection parameters, and configuring access authorizations (i.e., permissions, privileges).

Privileged accounts, including super user accounts, are typically described as system administrator for various types of commercial off-the-shelf operating systems. Restricting privileged accounts to specific personnel or roles prevents day-to-day users from having access to privileged information or functions. Organizations may differentiate in the application of this requirement between allowed privileges for local accounts and for domain accounts provided organizations retain the ability to control system configurations for key security parameters and as otherwise necessary to sufficiently mitigate risk.

NIST SP 800-171 Rev. 2, discussion under 3.1.5. Whitespace normalised; wording unchanged.

Assessment objectives

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

[a] privileged accounts are identified
[b] access to privileged accounts is authorized in accordance with the principle of least privilege
[c] security functions are identified
[d] access to security functions is authorized in accordance with the principle of least privilege

NIST SP 800-171A, determination statements for 3.1.5.

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

Access control policy
procedures addressing account management
procedures addressing least privilege
system security plan
system design documentation
list of system-generated privileged accounts
list of system administration personnel
system audit logs and records
system configuration settings and associated documentation
other relevant documents or records

Interview

Personnel with responsibilities for defining least privileges necessary to accomplish specified tasks
personnel with information security responsibilities
system or network administrators

Test

Mechanisms implementing least privilege functions

NIST SP 800-171A, potential assessment methods and objects for 3.1.5.

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 3 points. Not meeting this requirement subtracts 3 from your 110-point SPRS score.

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 reworded: 03.01.05 Least Privilege. It gains organization-defined parameters.

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)