NIST SP 800-171 Rev. 3 3.10.6 — Alternate Work Site

What this control requires

This control requires determining and documenting the alternate work sites allowed for use by employees and applying specific security requirements at these sites to protect Controlled Unclassified Information (CUI) during contingency operations. Security measures are tailored based on the activities conducted at each site. This control supports the Alternate Work Site Management capability within the Physical Protection (3.10) family.

In plain English

This control requires determining and documenting the alternate work sites allowed for use by employees and applying specific security requirements at these sites to protect Controlled Unclassified Information (CUI) during contingency operations. In practice, this means you can prove you information management-level controls on a defined cadence.

Why it matters

DoD contractors and their subcontractors must implement all 100 SP 800-171 requirements to keep CUI handling contracts. Gaps are scored against the SPRS scoring methodology; below a 110-point starting score, each unmet requirement deducts points and a below-threshold score can disqualify a bid.

What an auditor looks for

A C3PAO conducting a CMMC Level 2 assessment uses NIST SP 800-171A objectives. They expect a System Security Plan (SSP), Plan of Action & Milestones (POA&M) for any gaps, and objective evidence (configurations, ticket records, training records) for every requirement.

Within Physical Protection, the assessor will trace your implementation back to the catalogue reference (Requirement 3.10.6) and look for objective evidence on the latest two assessment cycles.

How to implement

Policy Management

Docs. Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA.

Operational checklist

• Information. Document the trigger, the owner and the cadence.
• Protection. Document the trigger, the owner and the cadence.
• Physical. Document the trigger, the owner and the cadence.
• Alternate. Document the trigger, the owner and the cadence.
• Risk. Document the trigger, the owner and the cadence.
• Scope: management, cui, security, work site, protection, operations.

Evidence to collect

• Policy Document. A signed and version-controlled policy / standard / procedure document.
• Infra Scan. Continuous infrastructure-posture telemetry — AWS Config, Azure Policy compliance, GCP Organisation Policy, Wiz / Prisma findings.

Signed policy or standard documents the safeguard. Focus: Alternate Work Site.

Common pitfalls

• Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• ISO/IEC 27001:2022 A.5.1 — Policies for information security
• HIPAA (45 CFR Part 164) 164.308(a)(5)(i) — Security Awareness and Training
• NIST SP 800-53 Rev. 5 PE-17 — Alternate Work Site
• BSI C5:2020 SP-01 — Documentation, communication and provision of policies and instructions
• SOC 2 (2017 TSC) CC2.3 — External Communication on Internal Control Matters

Related controls in NIST SP 800-171 Rev. 3

• Requirement 3.14.3 — Security Alerts, Advisories, and Directives
• Requirement 3.15.1 — Policy and Procedures
• Requirement 3.8.4 — Media Marking
• Requirement 3.13.11 — Cryptographic Protection
• Requirement 3.4.11 — Information Location
• Requirement 3.10.2 — Monitoring Physical Access

References

• NIST Computer Security Resource Center — NIST SP 800-171 Rev. 3
• Catalogue identifier: Requirement 3.10.6

Topics: governance riskpolicy management