3.5.2Prove those identities

Authenticate identifiers before granting access.

IA
Level 1
5 pt
Rev. 3: Reworded

The requirement, verbatim

NIST SP 800-171 Rev. 2 · 3.5.2
Authenticate (or verify) the identities of users, processes, or devices, as a prerequisite to allowing access to organizational systems.

Requirement 3.5.2, practice name in the CMMC assessment guide: Authentication.

NIST's discussion

Individual authenticators include the following: passwords, key cards, cryptographic devices, and one-time password devices. Initial authenticator content is the actual content of the authenticator, for example, the initial password. In contrast, the requirements about authenticator content include the minimum password length. Developers ship system components with factory default authentication credentials to allow for initial installation and configuration. Default authentication credentials are often well known, easily discoverable, and present a significant security risk.

Systems support authenticator management by organization-defined settings and restrictions for various authenticator characteristics including minimum password length, validation time window for time synchronous one-time tokens, and number of allowed rejections during the verification stage of biometric authentication. Authenticator management includes issuing and revoking, when no longer needed, authenticators for temporary access such as that required for remote maintenance. Device authenticators include certificates and passwords.

NIST SP 800-63-3 provides guidance on digital identities.

NIST SP 800-171 Rev. 2, discussion under 3.5.2. Whitespace normalised; wording unchanged.

Assessment objectives

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

[a] the identity of each user is authenticated or verified as a prerequisite to system access
[b] the identity of each process acting on behalf of a user is authenticated or verified as a prerequisite to system access
[c] the identity of each device accessing or connecting to the system is authenticated or verified as a prerequisite to system access

NIST SP 800-171A, determination statements for 3.5.2.

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

Identification and authentication policy
system security plan
procedures addressing authenticator management
procedures addressing user identification and authentication
system design documentation
list of system authenticator types
system configuration settings and associated documentation
change control records associated with managing system authenticators
system audit logs and records
other relevant documents or records

Interview

Personnel with authenticator management responsibilities
personnel with information security responsibilities
system or network administrators

Test

Mechanisms supporting or implementing authenticator management capability

NIST SP 800-171A, potential assessment methods and objects for 3.5.2.

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 reworded: 03.05.02 Device Identification and Authentication. 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)