3.1.8Lock accounts after repeated failed logins

Cap how many wrong passwords an attacker can try before the account stops answering.

AC
Level 2
1 pt
Rev. 3: Reworded

The requirement, verbatim

NIST SP 800-171 Rev. 2 · 3.1.8
Limit unsuccessful logon attempts.

Requirement 3.1.8, practice name in the CMMC assessment guide: Unsuccessful Logon Attempts.

NIST's discussion

This requirement applies regardless of whether the logon occurs via a local or network connection. Due to the potential for denial of service, automatic lockouts initiated by systems are, in most cases, temporary and automatically release after a predetermined period established by the organization (i.e., a delay algorithm). If a delay algorithm is selected, organizations may employ different algorithms for different system components based on the capabilities of the respective components. Responses to unsuccessful logon attempts may be implemented at the operating system and application levels.

NIST SP 800-171 Rev. 2, discussion under 3.1.8. Whitespace normalised; wording unchanged.

Assessment objectives

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

[a] the means of limiting unsuccessful logon attempts is defined
[b] the defined means of limiting unsuccessful logon attempts is implemented

NIST SP 800-171A, determination statements for 3.1.8.

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 unsuccessful login attempts
system security plan
system design documentation
system configuration settings and associated documentation
system audit logs and records
other relevant documents or records

Interview

Personnel with information security responsibilities
system developers
system or network administrators

Test

Mechanisms implementing access control policy for unsuccessful login attempts

NIST SP 800-171A, potential assessment methods and objects for 3.1.8.

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 1 point. Not meeting this requirement subtracts 1 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: 03.01.08 Unsuccessful Logon Attempts. 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)