---
title: "NIST 800-171 3.5.8 (IA.L2-3.5.8): Password Reuse"
description: "NIST SP 800-171 3.5.8 Password Reuse: 1 SPRS point, allowed on a CMMC POA&M. The text, what assessors check and the evidence."
url: https://policycortex.com/nist-800-171/identification-and-authentication/3.5.8
sealed: 2026-11-11
amended: 2026-11-11
register: nist-800-171/identification-and-authentication/3.5.8
records: 7
digest: sha3:62ca623bf3921010efd7ef1a94ef6bf5daa2c0ec009dbf2a65c0b52d84761fda
---

# NIST 800-171 3.5.8 (IA.L2-3.5.8): Password Reuse

NIST 800-171 / Identification and Authentication / 3.5.8

"Prohibit password reuse for a specified number of generations." ([NIST SP 800-171 Rev. 2, requirement 3.5.8](https://doi.org/10.6028/NIST.SP.800-171r2))

CMMC Level 2 practice IA.L2-3.5.8.

## What 3.5.8 means in practice

Users cannot cycle back to a recent password. Specify how many earlier passwords are remembered (24 is a common choice) and enforce it in every system that manages passwords, usually with a minimum password age so the history cannot be flushed in one sitting.

## SPRS points and the CMMC POA&M

- **CMMC Level 2 practice**: IA.L2-3.5.8
- **SPRS points**: 1 point. When it is not met, the DoD Assessment Methodology subtracts 1 from the score of 110.
- **CMMC POA&M**: Allowed. It is worth 1 point, and 32 CFR 170.21(a)(2)(ii) admits requirements worth 1 point. Conditional status also needs a score of at least 88, and the item must be closed within 180 days.

Sources: [NIST SP 800-171 DoD Assessment Methodology, version 1.2.1 (June 24, 2020), Annex A](https://www.acq.osd.mil/asda/dpc/cp/cyber/docs/safeguarding/NIST-SP-800-171-Assessment-Methodology-Version-1.2.1-6.24.2020.pdf); [32 CFR 170.21, Plan of Action and Milestones requirements](https://www.ecfr.gov/current/title-32/section-170.21).

## What an assessor checks for 3.5.8

NIST SP 800-171A gives 2 determination statements for 3.5.8, each found satisfied or other than satisfied. Determine if:

- 3.5.8[a] the number of generations during which a password cannot be reused is specified.
- 3.5.8[b] reuse of passwords is prohibited during the specified number of generations.

[NIST SP 800-171A (June 2018), assessment objectives for 3.5.8](https://doi.org/10.6028/NIST.SP.800-171A)

## Evidence that shows 3.5.8 is met

- The specified number of remembered passwords.
- Password history settings in the identity provider and directories.
- The same settings in applications that keep their own passwords.

## How PolicyCortex gathers the evidence

PolicyCortex reads this evidence with the collectors below, read only, and grades 3.5.8 from it. Each line says what the product checks.

- **Okta: Policies.** Checks that every active Okta password policy remembers at least 24 earlier passwords and keeps a new password for at least a day.
- **AWS: IAM.** Checks the AWS account password policy against a baseline that prevents reuse of the last 24 passwords.

## Related pages

- **Calculator**: [SPRS score calculator: mark 3.5.8 and the other 109 requirements and see the score.](https://policycortex.com/sprs-score-calculator#family-IA)
- **Sample package**: [Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.](https://policycortex.com/sample-package)
- **Family**: [All 11 Identification and Authentication requirements (3.5).](https://policycortex.com/nist-800-171/identification-and-authentication)
- **Previous**: [3.5.7: Password Complexity](https://policycortex.com/nist-800-171/identification-and-authentication/3.5.7)
- **Next**: [3.5.9: Temporary Passwords](https://policycortex.com/nist-800-171/identification-and-authentication/3.5.9)
- **All requirements**: [All 110 NIST SP 800-171 requirements, by family.](https://policycortex.com/nist-800-171)

Meet the requirement once. Keep the evidence current. [Request Access](https://app.policycortex.com/auth?mode=request-access) · [Book a call](https://policycortex.com/book)

## Register colophon

| Seq | Label | SHA3-256 | Prev |
|---|---|---|---|
| REC 0000 | REQUIREMENT | 82187d37aa91 | 98d912302d09 |
| REC 0001 | MEANING | 889aa4d08090 | 82187d37aa91 |
| REC 0002 | POINTS AND POA&M | 54c0c1bc2f43 | 889aa4d08090 |
| REC 0003 | ASSESSMENT OBJECTIVES | a6c47a84ec88 | 54c0c1bc2f43 |
| REC 0004 | EVIDENCE | 8797d2721818 | a6c47a84ec88 |
| REC 0005 | COLLECTORS | 68aef41e3486 | 8797d2721818 |
| REC 0006 | RELATED | 62ca623bf392 | 68aef41e3486 |

Head sha3:62ca623bf3921010efd7ef1a94ef6bf5daa2c0ec009dbf2a65c0b52d84761fda. Each digest is SHA3-256 over the previous digest, the register key, the record label, and the record copy; a second party can recompute it from this document.