- Configure the threshold and lockout behavior in each place authentication happens — identity provider, operating systems, VPN — and record what you chose.
- Prefer throttling or time-boxed lockout over permanent lockout, which converts the requirement into a denial-of-service tool against your own staff.
3.1.8OFFICIAL STATEMENT BELOWDERIVED REQUIREMENTPENDING NIST SME REVIEW
3.1.8 — Unsuccessful logon attempts
3.1 Access Control · NIST SP 800-171 Rev. 2 · The heading label is this site's navigational shorthand; the official language is the statement below.
Official requirement statement (verbatim)
Limit unsuccessful logon attempts.
NIST SP 800-171 Rev. 2 — Protecting CUI in Nonfederal Systems ↗NIST SP 800-171A — Assessing Security Requirements for CUI ↗Independent interpretation
What this requirement is after
Password guessing gets a small number of tries, then the door slows or shuts. Lockout or progressive throttling after failed attempts turns brute force from an overnight certainty into a noisy failure.
Mapped practices
Brilliant at the Basics practices that support this requirement
No practice maps to this requirement — deliberately.
The campaign’s twenty practices are a priority list, not a control catalog, and none of them works this requirement’s substance directly. It still applies to you if it is in your contract’s scope: address it through your own implementation and the related artifacts below, and treat the absence of a mapping here as honesty, not permission to skip it.
Doing the work
Implementation considerations and evidence
- Lockout or smart-lockout policy exports from each authentication point
- Sampled lockout events showing the mechanism operating
Artifacts
Templates and worksheets with a mapped relationship
No artifact in the library names this requirement yet. The library index groups everything by category and practice.
The other revision
Where this lands in Rev. 3
Provenance
Sources and review status
| Primary sources | NIST SP 800-171 Rev. 2 — Protecting CUI in Nonfederal Systems · NIST SP 800-171A — Assessing Security Requirements for CUI |
|---|---|
| Review status | Pending NIST SME review |
| Content version | 1.0 |
| Updated |