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NIST SP 800-171 CUI Protection Center

03.01.08 — Unsuccessful Logon Attempts

Read the official CUI requirement and assessment content, then use the separately labeled Bare Metal Cyber perspective to connect it to implementation, evidence, and sustained operation.

4Parameters
1Source controls
2Assessment objectives
3Assessment methods

03.01 — Access Control · NIST SP 800-171 Revision 3

Active
Official NIST requirement content

Security requirement

  1. a.Enforce a limit of [Organization-defined: number] consecutive invalid logon attempts by a user during a [Organization-defined: time period].
  2. b.Automatically [Organization-defined: SELECTED PARAMETER VALUES] when the maximum number of unsuccessful attempts is exceeded.
Official NIST discussion

Discussion

Due to the potential for denial of service, automatic system lockouts are in most cases, temporary and automatically release after a predetermined time period established by the organization (i.e., using a delay algorithm). Organizations may employ different delay algorithms for different system components based on the capabilities of the respective components. Responses to unsuccessful system logon attempts may be implemented at the system and application levels. Organization-defined actions that may be taken include prompting the user to answer a secret question in addition to the username and password, invoking a lockdown mode with limited user capabilities (instead of a full lockout), allowing users to only logon from specified Internet Protocol (IP) addresses, requiring a CAPTCHA to prevent automated attacks, or applying user profiles, such as location, time of day, IP address, device, or Media Access Control (MAC) address.

Official organization-defined parameters

Tailoring decisions required

Resolve these values through the governing organization’s approved tailoring and risk-management process before declaring the requirement implemented.

numberorganization-defined numberthe number of consecutive invalid logon attempts by a user allowed during a time period is defined.
time periodorganization-defined time periodthe time period to which the number of consecutive invalid logon attempts by a user is limited is defined.
SELECTED PARAMETER VALUES
time periodorganization-defined time periodthe time period for an account or node to be locked is defined (if selected).
Bare Metal Cyber interpretation

Implementation perspective

Treat Unsuccessful Logon Attempts as a CUI protection outcome that must be reflected in the system boundary, documented implementation, operational behavior, and assessment evidence. Pay particular attention to approved identities, least privilege, remote access, information flow, and the full account lifecycle.

  1. Confirm the requirement is in scope for the CUI system components, services, users, and external connections being assessed.
  2. Resolve every organization-defined parameter through an approved governance and tailoring process.
  3. Map each clause of the requirement to an accountable owner, implementation mechanism, and evidence source.
  4. Verify that inherited and shared implementations are supported by current provider evidence and responsibility boundaries.
  5. Collect evidence during normal operation and review changes, exceptions, and deficiencies on a risk-based cadence.

Questions to ask

  • Which CUI assets, data flows, users, and services are protected by this 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

  • access authorization and approval records
  • account inventories and entitlement exports
  • access review results
  • authentication and authorization logs

Common failure patterns

  • CUI access that exceeds mission need
  • shared or orphaned accounts
  • remote access paths outside the approved boundary
  • access reviews that cannot be reconciled to deployed permissions
Official NIST SP 800-171A content

Assessment objectives and methods

Assessment objectives (2)
  1. a.

    a limit of [Organization-defined: number] consecutive invalid logon attempts by a user during [Organization-defined: time period] is enforced.

  2. b.

    [Organization-defined: SELECTED PARAMETER VALUES] when the maximum number of unsuccessful attempts is exceeded.

Examine

  • access control policy and procedures
  • procedures for unsuccessful logon attempts
  • system design documentation
  • system audit records
  • system configuration settings
  • system security plan
  • other relevant documents or records

Interview

  • personnel with information security responsibilities
  • system developers
  • system administrators

Test

  • mechanisms for implementing the access control policy for unsuccessful logon attempts
Official source-control relationships

Source NIST SP 800-53 controls

These controls are referenced by the official SP 800-171 Rev. 3 OSCAL record. Open the corresponding control pages for complete control text, enhancements, D3FEND mappings, and related learning.

Source controlAC-7Open SP 800-53 control →
Source record

Authoritative sources

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.