03.01.08: Unsuccessful Logon Attempts

To meet the 03.01.08: unsuccessful logon attempts requirement, configure every in-scope system that processes, stores, or transmits CUI to limit and respond to repeated failed logon attempts (for example, lockout, delay, or other automated restrictions) and prove it works with settings evidence and test results. Document the chosen thresholds, where they’re enforced, and how exceptions are controlled. ¹

Key takeaways:

• Enforce unsuccessful logon attempt controls at the system control point (IdP, OS, VPN, application), not only in a policy. ¹
• Define measurable parameters (attempt threshold, lockout/delay behavior, reset conditions) and apply them consistently across the CUI boundary. ¹
• Keep assessor-ready evidence: config snapshots + test proof + SSP mapping + POA&M for gaps. ¹

03.01.08 is a straightforward requirement that often fails in practice because teams implement it unevenly. The control is not “have a password policy.” It is “make repeated failed logons stop working” across the systems that protect your CUI environment. Assessors will look for two things: (1) a clear, documented implementation decision (what limits, where enforced, and why), and (2) proof the decision is actually enforced on the relevant authentication pathways. ¹

Operationally, unsuccessful logon attempt controls sit at the intersection of identity, endpoint hardening, remote access, and application security. If you rely on an identity provider (IdP) for SSO, you still need to confirm local and fallback paths (local admin, break-glass, service consoles, legacy apps, VPN appliances) are covered. If you have third parties administering systems, their access methods must be subject to the same controls, or you need a tightly governed exception with compensating controls and evidence. ¹

This page gives you requirement-level implementation guidance you can put into an SSP, assign to system owners, validate with tests, and defend during an assessment.

Regulatory text

Requirement: “NIST SP 800-171 Rev. 3 requirement 03.01.08 (Unsuccessful Logon Attempts).” ¹

What the operator must do: Implement technical controls that restrict or otherwise respond to repeated failed logon attempts on in-scope systems. Your implementation must be defined, consistently applied across the CUI environment, and supported by operating evidence that shows the control is enforced in production. ¹

Plain-English interpretation (what this really means)

If a user (or attacker) keeps guessing credentials, your systems must automatically stop accepting unlimited guesses. You meet 03.01.08 by setting a clear rule (attempt limit and response) and enforcing it where authentication happens. ¹

“Unsuccessful logon attempts” is broader than interactive Windows logons. Treat every authentication surface as in scope if it can reach CUI systems or administrative functions, including:

• SSO/IdP sign-ins
• VPN / ZTNA portals
• Privileged access gateways and jump hosts
• Local OS logons (workstations and servers)
• SaaS admin consoles used for CUI workflows
• Application logons for internally hosted CUI apps ¹

Who it applies to (entity + operational context)

Applies to: Nonfederal organizations handling CUI for the U.S. Government, including defense and federal contractors, on the systems and services within the defined CUI boundary. ¹

Operational contexts where 03.01.08 commonly breaks:

• Mixed auth stack (SSO for most apps, local accounts still enabled on endpoints/servers)
• Multiple remote access paths (VPN plus admin interfaces)
• Third-party support accounts with different policies
• Legacy apps that do not integrate cleanly with centralized identity ¹

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

Use this as an implementation checklist you can assign to control owners.

Step 1: Define the enforcement points (where failed logons happen)

Create an inventory of authentication control points for the CUI boundary:

• Primary IdP (SSO)
• Endpoint OS (workstations and servers)
• Remote access (VPN/ZTNA)
• Privileged access tooling (PAM, bastions)
• Critical applications that authenticate locally ¹

Deliverable: “Authentication Pathways” list mapped to system owners.

Step 2: Choose your unsuccessful logon handling approach

Pick a consistent approach per control point:

• Account lockout after a defined number of failed attempts
• Progressive delays / throttling after repeated failures
• Temporary suspension with admin reset or time-based reset

Write down the parameters you will enforce for each pathway:

• Attempt threshold (count)
• Lockout or delay behavior
• Lockout duration or delay curve
• Reset conditions (time-based reset, admin reset, successful auth resets counter)
• Treatment of privileged accounts and break-glass accounts ¹

Practical constraint: Some systems (especially SaaS) may only offer throttling or adaptive protections. Capture what the platform enforces and treat gaps as POA&M items with compensating controls. ¹

Step 3: Configure controls in the platforms that matter

Typical configuration actions (adjust to your stack):

• IdP: Set failed login attempt handling, suspicious sign-in protections where available, and consistent policy scopes for users that access CUI.
• Windows/macOS/Linux: Enforce account lockout policy (or equivalent) for local accounts; ensure it applies to endpoints inside the CUI boundary.
• VPN/ZTNA: Enforce attempt limits on the portal and on any local user database (if present).
• PAM/bastions: Enforce the same controls on the PAM login and any downstream access methods. ¹

Control-owner reality check: If you cannot technically enforce the control on a pathway, that pathway is a scope problem. Either remove it from the CUI boundary (architectural change) or govern it as a documented exception with compensating controls and approval. ¹

Step 4: Handle service accounts, API tokens, and non-interactive access

Unsuccessful “logon attempts” can show up as repeated failed authentications from services too. Decide how you will treat:

• Service accounts with passwords (reduce use; enforce strong governance)
• API keys/tokens (detect repeated failures; alert and rotate)
• SSH keys (detect repeated failed key attempts; rate limit where possible) ¹

Expectation to set internally: Non-interactive identities still need protections against brute force and credential stuffing patterns, even if the enforcement mechanism differs.

Step 5: Implement monitoring + response hooks (make it operational)

03.01.08 is stronger when you can show you detect patterns and act:

• Centralize authentication logs (IdP, VPN, OS security logs, application auth logs)
• Create alerts for:
  • Multiple failures followed by a success (possible password guessing)
  • High-volume failures from a single source
  • Failures targeting privileged accounts
• Define an operational playbook: investigate, reset, disable, require password reset, review source IPs, and document outcome. ¹

Step 6: Test it like an assessor will

For each enforcement point, run a controlled test in a non-production environment where feasible, or a tightly controlled production test:

• Attempt authentication with a known test account and intentionally fail until the limit triggers
• Capture evidence of lockout/throttle behavior
• Capture evidence of reset behavior (admin reset or time-based reset)
• Confirm behavior is consistent for remote access and privileged access paths ¹

Step 7: Document in SSP and track gaps in a POA&M

In your SSP, include:

• Control statement for 03.01.08
• Implementation description per enforcement point
• Roles: control owner, system owner, IAM owner, SOC/IT operations owner
• Frequency for reviewing configurations and alert tuning ¹

In your POA&M, track:

• Systems where you cannot enforce the chosen parameters
• Compensating controls, planned remediation, and closure validation steps ¹

Where Daydream fits naturally: Daydream helps you keep the SSP control narrative, system mappings, evidence uploads (config exports, screenshots, test outputs), and POA&M remediation status in one place so you can answer assessor questions without hunting across tickets and admin consoles.

Required evidence and artifacts to retain

Assessors want proof the control exists and operates. Keep evidence per enforcement point.

Evidence checklist (retain current + prior versions per your retention standard):

• SSP section for 03.01.08 with system mapping and ownership ¹
• Configuration exports or screenshots showing:
  • Attempt limit policy
  • Lockout/throttle settings
  • Reset/unlock behavior ¹
• Test results:
  • Step-by-step test script
  • Timestamped outcomes showing lockout/throttle triggered
  • Ticket or change record approving the configuration ¹
• Logging/monitoring artifacts:
  • Sample auth logs showing failed attempts and enforcement
  • Alert rules (titles, logic, and routing)
  • Incident/runbook references ¹
• Exception register entries (if any) plus compensating controls and approvals
• POA&M items with closure evidence when remediated ¹

Common exam/audit questions and hangups

Expect these questions and prepare crisp answers with evidence.

1. “Where is this enforced?”
   Have a one-page map: IdP, VPN, endpoints, privileged access, and app logons, each with the control setting reference. ¹

2. “What are your parameters and why?”
   Provide the chosen thresholds and behavior per platform, plus rationale tied to your environment constraints. Avoid “defaults” as the only justification. ¹

3. “Show me it works.”
   Produce a recent test record and a configuration snapshot from production (or a controlled environment that matches production). ¹

4. “How do you handle privileged and break-glass accounts?”
   Explain how they are protected (same enforcement or compensating controls) and how unlock/reset is governed. ¹

5. “Do third parties get different rules?”
   Your answer should be “no,” unless you have a documented exception with compensating controls and risk acceptance. ¹

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails assessments	How to avoid it
Policy-only control (“users lock out after X attempts”)	No proof the systems enforce it	Collect config evidence per enforcement point and test results. 1
SSO configured, local accounts ignored	Attackers target local/legacy paths	Disable local logon where possible; enforce local lockout where required; document exceptions. 1
One setting for users, different for admins without governance	Privileged accounts become the weakest link	Define privileged account handling explicitly; require approvals for exceptions. 1
Lockout creates helpdesk pain, so teams turn it off	Control stops operating	Use throttling where lockout is risky; pair with monitoring and clear unlock procedures. 1
No log visibility into failures	You can’t prove operation or detect attacks	Centralize auth logs and retain sample records tied to tests/incidents. 1

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement. From a risk standpoint, repeated unsuccessful logons are a common early signal for credential attacks. If 03.01.08 is weak or inconsistently enforced, brute-force and password-spraying attempts have more opportunity to succeed, especially against older protocols, remote access portals, and privileged accounts. ¹

Practical execution plan (30/60/90-day)

No time-based implementation durations are specified in the provided sources. Use these phases as an operational cadence you can adapt.

Days 0–30: Get to a defensible baseline

• Confirm CUI boundary and list all authentication pathways into it. ¹
• Pick standard parameters for unsuccessful logon handling per platform type (IdP, OS, VPN, PAM, apps). ¹
• Implement the settings on the highest-risk entry points first: remote access and privileged access. ¹
• Draft SSP language and assign named owners.

Days 31–60: Prove operation and close obvious gaps

• Run tests for each enforcement point and store results as evidence. ¹
• Centralize log sources and add initial alerts for high-volume failures and failures followed by success. ¹
• Identify systems that can’t meet the standard; open POA&M items with compensating controls and target remediation. ¹

Days 61–90: Make it steady-state

• Add configuration review checks to change management (so settings don’t drift). ¹
• Validate third-party access methods and contract/administration pathways follow the same control. ¹
• Conduct a tabletop on credential attack response using your auth alerts and runbook.
• Update SSP/POA&M with “as-operated” reality and closure evidence. ¹

Frequently Asked Questions

Does 03.01.08 require a specific lockout threshold (like “5 attempts”)?

The provided regulatory excerpt does not specify a numeric threshold. Set measurable parameters you can justify and enforce consistently across in-scope authentication pathways, then document and test them. ¹

If we use an IdP with SSO, is that enough?

Only if SSO is the only viable authentication path. You still need to address local OS logons, VPN portals, admin consoles, and any application that authenticates outside the IdP. ¹

How do we handle privileged accounts without locking out administrators during an incident?

Define privileged account handling explicitly and use compensating controls where lockout is operationally risky (for example, throttling plus monitoring and controlled reset procedures). Document approvals and keep evidence. ¹

Are service accounts in scope for unsuccessful logon attempts?

If they authenticate to in-scope systems, treat repeated failures as a control concern. Your enforcement method may differ (alerting, throttling, rotation), but you should document how you prevent unlimited guessing and prove it operates. ¹

What evidence will an assessor ask for first?

Expect configuration proof from the main enforcement points (IdP/VPN/OS) and a test record showing failed attempts trigger the configured restriction. Also be ready to show where this is described in your SSP. ¹

We have one legacy app that can’t lock out users. Can we still pass?

Treat it as a gap: document it in the POA&M, apply compensating controls (network restrictions, SSO front-end, monitoring), and show a remediation plan with closure validation criteria. ¹

Footnotes

1. NIST SP 800-171 Rev. 3