SI-4(1): System-wide Intrusion Detection System

To meet the si-4(1): system-wide intrusion detection system requirement, you must connect and configure your individual intrusion detection tools so they operate as one coordinated, enterprise-wide detection capability (for example: centralized collection, correlation, alerting, and response routing). Your goal is consistent visibility and detection coverage across networks, hosts, cloud, and key enclaves, with provable, repeatable operation. ¹

Key takeaways:

• Build a single detection “fabric”: centralized telemetry + correlation + alert workflow, not isolated point tools. ¹
• Scope and ownership matter as much as technology: define system boundaries, data sources, and who triages and closes alerts. ²
• Keep assessor-ready evidence: architecture, configurations, log/alert samples, and recurring verification that connectors and detections still work. ²

SI-4(1) is an operational control enhancement: it expects you to move from “we have some intrusion detection tools” to “we have a connected, system-wide intrusion detection system.” The work is less about buying a new platform and more about making the tools you already run behave like a single capability: consistent sensor coverage, centralized collection, normalized data, correlation rules, alert routing, and a closed-loop process that proves detections are monitored and acted on. ¹

For a Compliance Officer, CCO, or GRC lead, the fastest path to operationalizing SI-4(1) is to treat it like an integration requirement with measurable acceptance criteria: which environments are in scope, which telemetry sources must report centrally, what “healthy” ingestion looks like, who owns triage, and what evidence you will produce every audit cycle. If your organization supports federal systems or handles federal data in contractor environments, SI-4(1) is commonly evaluated as part of a broader NIST SP 800-53 control set, so weak integration or missing evidence tends to surface quickly in assessments. ²

Regulatory text

Requirement (excerpt): “Connect and configure individual intrusion detection tools into a system-wide intrusion detection system.” ¹

What the operator must do

You must demonstrate that intrusion detection is not fragmented. Practically, this means:

• Your sensors/tools (network IDS, host agents, cloud detection, application/WAF signals, identity signals where applicable) feed into a coordinated detection capability.
• Alerts are consolidated (or at least centrally visible), correlated, routed, and handled through a defined process.
• The integration is configured and maintained, not a one-time hookup. ¹

Plain-English interpretation

SI-4(1) expects “system-wide” detection coverage with integrated operations. Auditors are usually testing for three outcomes:

1. Coverage: critical environments are monitored, not just a subset.
2. Connectivity: sensors actually send telemetry to the central place you claim (SIEM, XDR, MSSP portal, SOC platform).
3. Operational use: someone is watching, triaging, and documenting outcomes, with evidence that the system works as designed. ²

A common misconception: SI-4(1) does not require a specific brand or a single monolithic tool. It requires that your tools operate as a coherent, enterprise detection system with centralized visibility and coordinated handling. ¹

Who it applies to (entity and operational context)

Entities commonly in scope:

• Federal information systems.
• Contractor systems handling federal data. ¹

Operational contexts where SI-4(1) becomes “make or break”:

• Hybrid environments (on-prem + multiple clouds) where detection is split across consoles.
• M&A / multiple business units with separate SOC stacks.
• Outsourced SOC/MSSP where your tooling exists, but integration and evidence are weak.
• Segmented enclaves (e.g., regulated workloads) where logging routes differ from enterprise defaults. ²

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

Step 1: Define the “system-wide” boundary in writing

Create a scoped statement that an assessor can test:

• Systems/environments in scope (prod, corp, endpoints, cloud accounts/subscriptions, key VPC/VNETs).
• Authoritative tooling stack (which products generate detections, which platform centralizes them).
• Central monitoring location (SIEM/XDR/SOC platform) and who monitors it. ²

Operator tip: If you can’t draw the boundary, you can’t prove “system-wide.”

Step 2: Inventory intrusion detection tools and telemetry sources

Build a list that includes:

• Network IDS/NSM sensors, EDR agents, cloud-native detections, WAF, email security, DNS security, identity signals where you route them into detection.
• For each: what events are produced, where they go, and how alerts are generated. ²

Step 3: Establish the “connect” pattern (collection + transport + normalization)

Document and implement:

• Connectors/forwarders (agents, syslog, APIs, event hubs).
• Data routing (which accounts/enclaves send to which collectors).
• Normalization/mapping (common fields, timestamps, host identifiers) sufficient to correlate across sources. ¹

Acceptance criterion you can test: pick one endpoint, one server, one cloud resource, generate a benign test event in each, and confirm the central platform receives and labels it correctly.

Step 4: Configure correlation and alerting so it behaves like one system

Integration is more than log shipping. Configure:

• Correlation rules (cross-source detections like “EDR alert + suspicious auth + unusual DNS”).
• Severity mapping and routing rules (who gets paged/ticketed).
• Deduplication and suppression logic to prevent alert floods hiding real incidents. ²

Step 5: Implement operational workflows (triage → escalate → close)

Write and run a workflow that includes:

• Triage steps (what analysts check first, what context they pull).
• Escalation criteria (when to open an incident, when to involve system owners).
• Closure requirements (root cause, containment notes, evidence links). ²

If a third party runs monitoring (MSSP/SOC), require them to provide audit-ready outputs: alert queues, tickets, and SLAs mapped to your scope.

Step 6: Monitor health of the detection system (connectivity drift is constant)

Build recurring checks for:

• Sensor/agent coverage gaps (hosts without agents, networks without sensors).
• Ingestion failures (connector broken, API token expired, log pipeline throttled).
• Rule health (disabled rules, noisy rules, stale logic). ¹

Step 7: Make evidence production part of the operating rhythm

You want to be able to answer, quickly:

• “Show me enterprise coverage.”
• “Show me an alert from each major source.”
• “Show me who triaged it and what happened.” ²

How Daydream fits naturally: Daydream becomes useful once you standardize what “good” looks like for SI-4(1): a named owner, a documented procedure, and a recurring evidence set. Daydream can track control ownership, prompt evidence collection on schedule, and keep the artifacts tied to the control so you are not rebuilding the audit packet each cycle. ²

Required evidence and artifacts to retain

Keep evidence that proves both design (how it’s supposed to work) and operation (that it is working):

Design evidence

• IDS architecture diagram showing major environments and data flows into the central detection platform.
• Data source inventory (tools, log sources, connector method, destination).
• Configuration standards (naming, tagging, severity mapping, routing rules). ²

Operational evidence

• Screenshots/exports showing active connectors and ingestion status.
• Sample alerts from multiple sources with timestamps and routing outcomes.
• SOC tickets (or incident records) showing triage, escalation, and closure.
• Health check records: ingestion failure alerts, agent coverage reports, exception list with approvals.
• Change records for rule updates, connector changes, onboarding of new environments. ¹

Common exam/audit questions and hangups

Assessors tend to ask questions that reveal fragmentation. Expect:

• “What does ‘system-wide’ mean for your organization? Show scope boundaries.” ²
• “Which intrusion detection tools do you run, and where do their alerts land?”
• “Prove endpoints and cloud workloads are feeding the central platform.”
• “Show correlation or central triage. If tools alert in separate consoles, how do you ensure coordinated detection?”
• “Who owns SI-4(1) day-to-day, and what’s the recurring check that integration still works?” ¹

Hangups that slow audits:

• Unclear system boundary (teams argue what is “in scope” mid-audit).
• Data exists but is not searchable due to inconsistent fields/hostnames.
• Alerts exist but there is no ticket evidence that anyone responded. ²

Frequent implementation mistakes and how to avoid them

Mistake	Why it fails SI-4(1)	Avoidance pattern
Treating SI-4(1) as “we bought a SIEM”	Purchase does not prove connection and configuration across tools	Require per-source onboarding evidence and ingestion validation in the central platform. 1
Separate consoles with no central triage	Not “system-wide” in operation	Route alerts centrally or create a single SOC queue with documented handoffs and correlation. 2
No health monitoring for connectors	Pipelines silently break	Implement ingestion failure alerting and a recurring review of sensor coverage gaps. 1
Evidence is ad hoc	Audit becomes a scramble	Predefine the evidence pack and collect it on a schedule; store it with the control record (Daydream can manage this). 2

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so you should treat SI-4(1) primarily as an assessment and authorization readiness issue rather than a “find a fine amount” issue. The operational risk is straightforward: fragmented detection creates blind spots, slows triage, and makes it hard to prove monitoring coverage for regulated workloads or federal data environments. ²

A practical 30/60/90-day execution plan

First 30 days (stabilize scope + evidence)

• Name a control owner and backups for SI-4(1); document the system boundary and in-scope environments. ²
• Build the inventory of intrusion detection tools and log sources; identify where each one reports today.
• Define the “minimum viable system-wide” acceptance tests (example: one test event per major environment must arrive centrally with correct identifiers).
• Stand up an evidence binder structure (architecture, inventories, sample alerts, tickets, health checks). ¹

Days 31–60 (connect + correlate)

• Implement or fix connectors for the highest-risk gaps (common: cloud audit logs, endpoint coverage, network segments).
• Normalize key identifiers (asset ID/hostname, account/subscription, environment tags) so correlation works.
• Configure alert routing into a single queue (SOC platform/ticketing) with clear ownership.
• Run tabletop-style alert walkthroughs: pick sample alerts and verify triage and closure produce durable records. ²

Days 61–90 (operationalize + prove repeatability)

• Establish recurring health checks and a remediation workflow for ingestion failures and coverage gaps.
• Formalize rule lifecycle management (who approves new rules, who tunes noise, where changes are recorded).
• Produce a “last period” evidence pack with real artifacts: connector status exports, sample alerts across sources, and closed tickets.
• Put SI-4(1) on a recurring compliance calendar in Daydream so evidence collection and reviews do not depend on memory. ²

Frequently Asked Questions

Do we need a single SIEM to satisfy SI-4(1)?

The requirement is to connect and configure tools into a system-wide intrusion detection system, which usually means centralized visibility and coordinated triage. If you have multiple platforms, you need a clear operating model that still functions as one system and can be evidenced. ¹

Does “system-wide” include cloud and SaaS?

If those environments are in your system boundary for federal data or the assessed system, include them and connect their detection/log sources into your central detection capability. Document the boundary and prove telemetry flow for in-scope services. ²

What evidence is most persuasive to auditors?

Show an architecture/data-flow diagram, connector configuration status, and sample alerts from different sources tied to tickets with triage and closure notes. Evidence that repeats over time is stronger than one-off screenshots. ²

We outsource monitoring to a third party SOC. Are we still on the hook?

Yes. You can delegate operations, but you still need contracts, workflows, and evidence that the connected system-wide detection is operating for your in-scope environment. Require the third party to provide alert/ticket artifacts on a recurring basis. ²

How do we handle segmented enclaves or disconnected networks?

Document the exception, then implement the best available connection method (forwarders, periodic transfer, or enclave-local monitoring with centralized reporting) and keep evidence of how alerts are surfaced and acted on. The key is a defensible design plus operational proof. ¹

What is the fastest way to fail SI-4(1) during an assessment?

Claiming “system-wide” while key environments are not connected, or being unable to show ingestion health and triage records. Assessors test reality by sampling assets and following the telemetry trail to the SOC queue. ²

Footnotes

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

2. NIST SP 800-53 Rev. 5