AC-14(1): Necessary Uses

AC-14(1): Necessary Uses requires you to explicitly define which “necessary” operational activities are allowed to bypass or relax standard access restrictions (for example, in emergencies or mission-critical conditions), and to control, approve, monitor, and document those uses. To operationalize it quickly, publish an allowlist of necessary-use scenarios, bind them to pre-approved roles and time limits, and retain audit-ready evidence of each invocation. ¹

Key takeaways:

• Define “necessary use” as an allowlisted exception, not a vague justification, and connect each exception to a business/mission condition. ¹
• Put guardrails around necessary use: approvals, least privilege, time limits, logging, and post-use review. ²
• Keep evidence per event and per control cycle: policy, procedure, approvals, logs, and review outcomes. ²

AC-14 is the NIST SP 800-53 Access Control family control for “Permitted Actions Without Identification or Authentication,” and enhancement (1) focuses on necessary uses. In practice, this requirement shows up any time you allow an exception path: emergency access, break-glass accounts, maintenance modes, kiosk/guest access, degraded operations, or continuity procedures where normal authentication/authorization controls are not feasible.

For a CCO, GRC lead, or compliance operator, the fastest way to get this right is to treat necessary uses as a governed exception mechanism. You want a short, explicit list of allowed scenarios and a matching set of technical and procedural safeguards that constrain those scenarios to what is truly required. Assessors usually fail teams here for one of two reasons: (1) the organization can’t explain what “necessary” means operationally, or (2) the organization can explain it but can’t produce consistent evidence that necessary uses are approved, logged, and reviewed.

This page gives you requirement-level implementation guidance you can drop into your control register, SSP, policies, and audit packet for the ac-14(1): necessary uses requirement. ¹

Regulatory text

Requirement (excerpt): “NIST SP 800-53 control AC-14.1.” ¹

What the operator must do: Treat AC-14(1) as a mandate to (a) define which uses of the system are considered “necessary” when normal identification/authentication or standard access restrictions are bypassed or relaxed, (b) tightly constrain those uses, and (c) generate evidence that the exceptions are controlled and reviewed as part of your access control program. Your implementation should be understandable to an assessor without relying on tribal knowledge. ²

Plain-English interpretation (what “necessary uses” means)

“Necessary uses” are pre-defined, business-justified exception paths where the organization allows a limited set of actions that would otherwise be blocked by standard access controls. The word “necessary” should translate to: the organization has determined that without this exception, it cannot safely maintain operations, security, or continuity under specific conditions.

A practical interpretation that works well in audits:

• Necessary use is allowlisted (explicitly permitted scenarios, not open-ended discretion).
• Necessary use is bounded (who, what actions, what systems, when, and for how long).
• Necessary use is observable (logged with enough detail to reconstruct what happened).
• Necessary use is reviewed (someone accountable validates appropriateness after the fact). ²

Who it applies to (entity and operational context)

This requirement applies to:

• Federal information systems implementing NIST SP 800-53 controls. ²
• Contractor systems handling federal data where NIST SP 800-53 is flowed down contractually or used to meet program requirements. ²

Operational contexts where AC-14(1) typically becomes “real”:

• Break-glass / emergency administrator access.
• Out-of-band access for incident response or recovery.
• Local console access when identity providers are down.
• Temporary bypass during patching or critical maintenance windows.
• Kiosk/shared terminal use cases with compensating controls.

If you have no scenarios where actions occur without standard identification/authentication or without standard access restrictions, your implementation may be “not applicable,” but you still need a documented rationale and periodic confirmation that the situation hasn’t changed. ²

What you actually need to do (step-by-step)

Step 1: Inventory all “exception paths” that could qualify as necessary use

Build a list from interviews and architecture review. Start with:

• Identity: break-glass accounts, shared accounts, local admin, root access, service accounts with human use.
• Platforms: hypervisors, network devices, OT/ICS consoles, database admin paths.
• Processes: incident response, disaster recovery, data restoration, emergency change.

Deliverable: Necessary Use Candidate Register (system, scenario, owner, current controls).
Evidence: meeting notes, diagrams, account lists, PAM reports, runbooks.

Step 2: Decide which scenarios are truly “necessary,” then write them as an allowlist

For each candidate scenario, record:

• Trigger condition (what must be true to invoke it).
• Permitted actions (the minimum set of actions needed).
• Authorized roles (named roles, not “IT”).
• Time boundary (maximum duration, expiry behavior, re-approval rules).
• Compensating controls (extra logging, dual control, ticket requirement). ²

Deliverable: Necessary Uses Allowlist Standard (a short, controlled document).

Step 3: Bind each necessary use to a formal approval model

Pick one model per scenario:

• Pre-approval for well-defined emergencies (on-call SRE lead + security duty officer).
• Just-in-time approval via ticketing workflow for maintenance exceptions.
• Two-person rule for high-impact actions (requester + approver). ²

Deliverable: RACI + workflow diagrams + approval SLAs (your internal targets, not regulatory).

Step 4: Implement technical guardrails (don’t leave it purely procedural)

Common patterns:

• Privileged Access Management (PAM) “break-glass” with check-out, MFA, session recording where feasible.
• Conditional access policies and emergency access accounts with strict monitoring.
• Time-bound elevation (JIT) with automatic deprovisioning/revocation.
• Separate emergency credentials stored in a controlled vault with access logs.

Your goal: if someone claims “necessary use,” the system design should force them through the approved path or create a clear audit trail when they don’t. ²

Step 5: Logging and monitoring requirements (minimum viable auditability)

For each necessary-use scenario, specify:

• What logs are generated (authentication events, privilege elevation, commands, configuration changes).
• Where logs land (central SIEM/log store).
• Who reviews them and how quickly (operationally defined).
• What constitutes an alert (use outside trigger condition, extended duration, unusual actions). ²

Deliverable: Necessary Use Logging Matrix mapping scenario → log sources → retention owner → review owner.

Step 6: Post-use review and continuous improvement

Require a post-use review that answers:

• Was the trigger condition met?
• Were actions within allowed scope?
• Was access removed/expired as designed?
• Were any control gaps found, and were they remediated? ²

Deliverable: a lightweight Necessary Use Review Form attached to each ticket/incident, plus a recurring trend review in your access control governance forum.

Required evidence and artifacts to retain (audit packet)

Maintain artifacts at two levels: control design evidence and operational event evidence.

Design-time evidence (shows the control exists)

• Policy/standard defining necessary uses and ownership. ²
• Allowlist of necessary-use scenarios with scope boundaries. ¹
• Approval workflow documentation (RACI, ticketing workflow, runbooks).
• Technical configurations: PAM/JIT settings, conditional access rules, vault access policies.
• Logging matrix and monitoring playbooks.

Run-time evidence (shows the control operates)

• Tickets/incident records that triggered the necessary use.
• Approvals (who approved, when, why).
• Access logs (account checkout, elevation, session start/stop).
• Session transcripts/records where feasible.
• Post-use review and closure notes, including corrective actions.

If you want this to be low-friction, Daydream typically helps teams map AC-14(1) to a control owner, a repeatable implementation procedure, and a recurring evidence set so audits don’t become a log scavenger hunt. ¹

Common exam/audit questions and hangups

Expect assessors to probe the edges:

1. “Define ‘necessary’.” If your definition is subjective, you will struggle.
2. “Show me your list.” They will ask for the allowlist and one or more examples.
3. “Who can invoke it?” Role clarity matters; “admins” is rarely specific enough.
4. “What prevents abuse?” They want technical and procedural guardrails. ²
5. “Prove it’s monitored.” Show log sources, reviews, and outcomes.
6. “Show closure.” Evidence that access expires and exceptions don’t linger.

Frequent implementation mistakes and how to avoid them

Mistake	Why it fails in audits	Fix
“Necessary use” is a sentence in a policy with no scenarios	Un-testable requirement; no operational meaning	Create an allowlist with triggers, roles, scope, and time bounds
Break-glass exists, but approvals are informal (Slack/phone only)	No durable evidence	Require ticket linkage and recorded approval
Exceptions never expire	Turns into permanent privileged access	Enforce time-bound elevation and automated revocation
Logging exists but is not reviewed	Detectability gap	Assign reviewer, cadence, and documented outcomes
Shared accounts with no compensating controls	Accountability gap	Replace with individual access or add vault checkout + session logs

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so this guidance stays anchored to framework expectations rather than enforcement outcomes. ¹

Risk-wise, necessary-use pathways are high-value targets because they concentrate privilege and often bypass normal controls. If you can’t show strong governance, incident responders and assessors will treat these pathways as likely root causes for unauthorized access, lateral movement, or untracked configuration changes. ²

Practical 30/60/90-day execution plan

First 30 days (stabilize and define)

• Name a control owner and approver chain for necessary uses (security + operations).
• Build the candidate register of exception paths across priority systems.
• Draft the necessary-use allowlist standard with a small number of clearly bounded scenarios.
• Choose your evidence model: what you will store per invocation (ticket + logs + review). ²

By 60 days (implement guardrails and evidence)

• Implement or tighten PAM/JIT for break-glass and emergency admin paths.
• Configure centralized logging for each necessary-use scenario and validate event fields.
• Integrate approvals into your ticketing or incident workflow, including post-use review steps.
• Run a tabletop test: simulate an outage and validate you can invoke, log, and review the necessary use cleanly.

By 90 days (operate, measure, and harden)

• Perform recurring reviews of all necessary-use invocations; document outcomes and remediation.
• Reduce the allowlist by eliminating “convenience exceptions” that aren’t necessary.
• Add detection rules for out-of-policy invocations and missing post-use reviews.
• Package your audit-ready evidence: policy, allowlist, workflows, configs, and sample events. ²

Frequently Asked Questions

Do we need AC-14(1) if we never allow access without authentication?

If there are truly no scenarios where actions occur without standard identification/authentication or standard access restrictions, document “not applicable” with rationale and re-check periodically. Many environments still have break-glass or local-console scenarios that count. ²

What’s the difference between “necessary use” and a normal privileged access request?

Necessary use is an exception path tied to specific trigger conditions and tighter boundaries, often used under emergency, continuity, or degraded-operation conditions. Normal privileged access should follow standard identity, access request, and least-privilege processes. ²

Can we approve necessary use after the fact?

For some emergency scenarios, you can allow immediate invocation with rapid post-use review, but you still need a defined trigger condition, clear authorized roles, and complete logs. For planned maintenance, pre-approval is typically easier to defend. ²

What evidence is most persuasive to an assessor for AC-14(1)?

A short allowlist of scenarios, a repeatable approval workflow, and a sampled event showing ticket → approval → access logs → post-use review. Consistency across systems matters more than volume of documentation. ²

How do we handle third parties who need emergency access?

Put third-party emergency access behind the same necessary-use workflow: named roles, contractual/engagement boundaries, JIT time limits, and centralized logs. Avoid unmanaged shared credentials; require traceability to an individual. ²

How should we document necessary uses in our SSP or control narrative?

Describe the allowlisted scenarios, the technical enforcement points (PAM/JIT/vault/conditional access), the approval and review workflow, and where evidence is stored. Keep it specific enough that another operator could execute it during an outage. ²

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON

2. NIST SP 800-53 Rev. 5