Quick-reference card
| Field | Value |
|---|---|
| Control ID | SI-06 |
| Control Name | Security and Privacy Function Verification |
| Framework | NIST SP 800-53, Revision 5 |
| Control Family | System and Information Integrity |
| Baselines | HIGH |
| Relevance | System-level, First Party and Third Party |
| Risk Severity | Medium |
What this control requires
SI-06 requires organizations to verify that security and privacy functions within their systems operate correctly and to act when they don’t. This control goes beyond assuming your defenses work. It mandates a structured verification process that confirms each defined security and privacy function performs as intended during normal operations and critical system transitional states.
Verification must occur at specific trigger points. Organizations need to confirm correct operation when a system starts up, restarts, shuts down, or aborts. Verification also runs on demand when a privileged user issues the command, or at a frequency the organization defines. In practice, this means you can’t rely on a one-time deployment check and assume ongoing correctness.
When a verification test fails, the control requires two things. First, designated personnel must receive an alert, whether through hardware indicator lights, electronic notifications, or console messages. Second, the organization must take a defined action in response to anomalies, such as shutting down the system, restarting the affected service, or executing an alternative recovery procedure. The goal is to ensure that a failing security function never operates silently in a degraded state.
Why it matters
Most organizations invest heavily in deploying security controls but spend far less effort confirming those controls continue to work. SI-06 addresses that gap directly. Security and privacy functions can degrade silently after configuration changes, software updates, or system failures, and without active verification, your team won’t know until an auditor flags it or an incident exposes the failure.
Failure to maintain this control introduces audit risk and may result in certification withdrawal or regulatory findings. For organizations operating under the NIST SP 800-53 HIGH baseline, SI-06 is a required control. An auditor who finds no evidence of ongoing function verification will document a finding, and that finding can cascade into broader questions about the integrity of your entire security program.
The compliance risk extends beyond a single audit cycle. Repeated failure to verify security functions signals a systemic gap in operational discipline. Regulatory bodies and authorization officials interpret this pattern as evidence that the organization lacks the maturity to maintain its security posture over time.
Privacy function verification carries its own regulatory weight. Privacy controls must operate as approved by the senior agency official for privacy, and privacy attributes must be applied correctly. Failure to verify these functions can result in unauthorized data processing or access that violates both policy and law.
What attackers exploit
- Degraded security functions after updates. Attackers probe systems shortly after patches or configuration changes, knowing that security functions may fail to reinitialize correctly during transitional states.
- Unmonitored system restarts. A system that restarts without verifying its security stack gives attackers a window where protections like intrusion detection or access controls may be inactive.
- Stale verification schedules. Organizations that verify functions quarterly rather than continuously leave long windows where a failed control goes undetected.
- Alert fatigue and ignored notifications. When failed verification alerts aren’t routed to the right personnel or get lost in noise, anomalies persist without remediation.
How to implement
The core challenge with SI-06 is building a verification program that’s specific enough to catch real failures but sustainable enough to run continuously without overwhelming your operations team.
For your organization
Start by defining which security and privacy functions require verification. This definition should come from your system security plan and privacy plan, and it should map directly to the functions your authorization package claims are in place. Typical candidates include access control enforcement, encryption services, audit logging, intrusion detection, session management, and privacy attribute enforcement.
Next, establish your verification triggers and frequency. The control specifies three trigger conditions: system transitional states (startup, restart, shutdown, and abort), privileged user commands, and a defined periodic frequency. For transitional states, configure your systems to run integrity checks on security-critical services as part of the boot and shutdown sequences. Many operating systems and platforms support startup scripts or service health checks that can validate whether security functions loaded correctly.
Define who receives alerts when verification fails. Build a notification workflow that routes failed verification results to your security operations team through electronic alerts, system console messages, or both. Avoid routing these alerts into a general inbox where they’ll compete with lower-priority notifications.
Document the actions your organization will take when anomalies are discovered. The response could include shutting down the affected system, restarting the security service, isolating the system from the network, or escalating to incident response. The key is that the response is predefined and documented, not improvised at the time of failure.
Common mistakes include treating verification as a manual quarterly task rather than an automated continuous process, failing to verify privacy functions separately from security functions, and not testing the alert pipeline itself to confirm that notifications reach designated personnel. Organizations that use continuous monitoring processes can integrate function verification into their existing monitoring workflows, reducing the operational overhead.
The UpGuard Breach Risk platform supports continuous visibility into your external attack surface, which complements internal function verification by identifying gaps that degraded controls may create.
For your vendors
When assessing vendor compliance with SI-06, you need evidence that the vendor has moved beyond checkbox compliance into operational verification. Start your assessment by requesting the vendor’s system and information integrity policy, along with their procedures for security and privacy function verification.
Ask these questions during your vendor assessment:
- Which security and privacy functions does the vendor verify, and how is this list maintained?
- What system transitional states trigger verification, and how are these transitions logged?
- How frequently does automated verification run outside of transitional states?
- Who receives alerts when verification tests fail, and what is the average time to acknowledge?
- What actions does the vendor take when anomalies are discovered, and are these actions documented in a runbook?
Request specific evidence artifacts, including recent audit logs showing verification events during system startups and restarts, sample alerts from failed verification tests, and the documented response procedures for anomalies. A vendor who can produce logs of verification activity during recent system transitions demonstrates operational maturity. A vendor who can only point to a policy document without corresponding operational evidence is a red flag.
Watch for these warning signs: verification procedures that haven’t been updated since initial system deployment, no evidence of failed verification tests (which suggests the verification process itself may not be running), alert recipients who are no longer with the organization, and no documented response actions for discovered anomalies.
You can streamline vendor assessments and evidence collection using the UpGuard Vendor Risk platform, which centralizes questionnaire management and tracks vendor security posture over time.
Start a free trial to see how UpGuard helps you manage third-party compliance at scale.
Evidence examples
| Evidence Type | Example Artifact |
|---|---|
| Policy documentation | System and information integrity policy defining verification requirements, trigger conditions, and response actions |
| Verification procedures | Procedures addressing security and privacy function verification, including step-by-step instructions for each defined function |
| System design records | System design documentation and configuration settings showing how verification is built into startup, restart, shutdown, and abort sequences |
| Verification trigger inventory | List of system transitional states and defined frequencies that require security and privacy function verification |
| Alert and notification records | Alerts and notifications from failed security and privacy verification tests, including timestamps and recipient acknowledgments |
| Audit trail | System audit records showing verification events, test results, and response actions taken when anomalies were discovered |
| Security and privacy plans | System security plan and privacy plan documenting which functions require verification and how verification supports the overall control environment |
Cross-framework mapping
No cross-framework mappings are currently configured for this control.
Related controls
- CA-07 — Continuous Monitoring: Provides the ongoing monitoring framework within which security and privacy function verification operates as a specific, automated check.
- CM-04 — Impact Analyses: Ensures that planned changes to the system are analyzed for their effect on security functions, helping prevent verification failures after modifications.
- CM-06 — Configuration Settings: Establishes the baseline configuration that security function verification checks against, ensuring functions operate within approved parameters.
- SI-07 — Software, Firmware, and Information Integrity: Complements function verification by detecting unauthorized changes to software and firmware that could cause security functions to operate incorrectly.
Frequently asked questions
What is NIST SP 800-53 SI-06?
SI-06 is the NIST SP 800-53 control that requires organizations to verify their security and privacy functions operate correctly and to respond when verification tests fail. It applies to systems operating under the HIGH baseline and mandates verification during system transitional states such as startup, restart, shutdown, and abort. The control also requires alerting designated personnel when tests fail and taking predefined actions like system shutdown or service restart when anomalies surface.
What happens if SI-06 is not implemented?
Without SI-06 implementation, security and privacy functions can degrade or fail silently, leaving your systems unprotected without any operational indication. Auditors assessing HIGH-baseline systems will flag the absence of function verification as a finding, which can lead to certification delays, conditions on your authorization to operate, or withdrawal of existing authorizations. The lack of verification also means that failed privacy attribute enforcement may go undetected, creating regulatory exposure under data protection requirements.
How do you audit SI-06?
Auditors verify SI-06 by examining evidence that security and privacy functions are tested at defined transitional states, on privileged user command, and at the organization’s defined frequency. They review system audit records for verification events during recent startups and restarts, inspect alert logs to confirm that failed tests generated notifications to designated personnel, and evaluate the documented response actions taken when anomalies were discovered. Auditors also confirm that the list of verified functions aligns with what the system security plan and privacy plan define as required.
What system transitional states require security function verification?
NIST SP 800-53 defines four system transitional states that trigger security function verification: startup, restart, shutdown, and abort. During each of these transitions, security and privacy functions must be checked to confirm they initialize or terminate correctly. Startup and restart are particularly critical because security services that fail to load during boot can leave a system exposed without any visible indication until the next scheduled verification cycle.