NIST 800-171 3.1.4 (AC.L2-3.1.4): Separation of Duties

Separate the duties of individuals to reduce the risk of malevolent activity without collusion.

NIST SP 800-171 Rev. 2, requirement 3.1.4

CMMC Level 2 practice AC.L2-3.1.4Published 2026-11-11

What 3.1.4 means in practice

No single person should be able to carry out a sensitive task from start to finish alone. Typical splits: the person who requests a change does not approve it, the people who administer access do not also administer the audit logs, and developers do not release their own code to production. Where a small team cannot split a duty, assessors look for an independent review in its place.

SPRS points and the CMMC POA&M

CMMC Level 2 practice: AC.L2-3.1.4
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; 32 CFR 170.21, Plan of Action and Milestones requirements.

What an assessor checks for 3.1.4

NIST SP 800-171A gives 3 determination statements for 3.1.4, each found satisfied or other than satisfied. Determine if:

3.1.4[a] the duties of individuals requiring separation are defined.
3.1.4[b] responsibilities for duties that require separation are assigned to separate individuals.
3.1.4[c] access privileges that enable individuals to exercise the duties that require separation are granted to separate individuals.

NIST SP 800-171A (June 2018), assessment objectives for 3.1.4

Evidence that shows 3.1.4 is met

A list of the duties that require separation and the role assigned to each.
Role assignments showing different people hold the conflicting roles.
Change records in which the approver is not the requester.
A periodic access review that looks for conflicting role combinations.

How PolicyCortex gathers the evidence

No PolicyCortex collector reads the evidence for 3.1.4. Your team provides the evidence listed above.

Related pages

Calculator: SPRS score calculator: mark 3.1.4 and the other 109 requirements and see the score.
Sample package: Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.
Family: All 22 Access Control requirements (3.1).
Previous: 3.1.3: CUI Flow Control
Next: 3.1.5: Least Privilege
All requirements: All 110 NIST SP 800-171 requirements, by family.

Related records

Guides and articles describe the work. The evidence that work produces is described in three proof pages, the architecture page, and the two pages on authorization.

proof.state: Proof of State. What the environment was, as of a date someone else picks: point-in-time records, content hashed and chained.
proof.change: Proof of Change. Who or what altered the environment, under what authority, with before and after state hashes.
proof.agency: Proof of Agency. What a machine was permitted to do before it acted, what it did, and what would have stopped it.
architecture: Architecture. How the chain is built and where the evidence is stored in each delivery mode.
authorization: Continuous ATO. How an authorizing official's decision is recorded with its package, and how the authorized system is checked against it every hour.
baseline: NIST SP 800-53. The Low, Moderate and High baselines as evidence, with the SSP, SAR and POA&M generated from one record.