Harbor Plant / 06 / PRACTICE GUIDE
Passive OT monitoring and anomaly review
Avoid premature conclusions from a new flow or quiet sensor. Interpret observations through coverage, maintenance, time and process context.
Download guide and workpapersOriginal AI-assisted SecNet educational content; examples are fictional. Not a source organization publication or endorsement. Sources checked: 2026-10-21.
EVIDENCE REVIEW DESK
Move from observations to decisions.
Code here is a local policy model with no target connection. Passing model cases are not security approval or device tests.
Online sensor / Incomplete decision
Inspect an incomplete decision based on record existence or another positive signal. Consider denial cases alongside permitted use.
s => s.sensorOnline === trueOnline status is not proof of segment coverage or lossless capture. Do not generalize observations across the plant without time, segment and capture-loss context.
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01 / EXPLANATION
The sensor-visible world
An online sensor does not establish visibility across all OT traffic. Mirror location, directions, capture loss, time source and retention limit coverage. Harbor separates observed segments from unobserved areas. Capture loss means an unseen operation cannot simply be declared absent. Sensor installation and data transport also need site-specific review. This exercise captures no traffic and configures no sensor; it questions coverage of supplied synthetic observations. Keep coverage records aligned with the detection result revision so later reviewers know which claims the available records can actually support.
02 / EXPLANATION
A new flow is not always an attack
A first-seen connection in a fictional record may reflect maintenance, backup activity, shift changes or misidentification. First seen depends on sensor history; it does not mean first ever. Compare maintenance plans, asset-owner context and approved-flow drafts. Do not accept a maintenance explanation without its ticket and time scope either. Record claims, observations and alternative explanations separately. Correct classification in a model establishes neither malicious activity on an actual device nor authority for automated response. The exercise supports a defensible question for the responsible site team.
03 / EXPLANATION
Protocol and process context
A protocol label does not establish that an operation is legitimate. Similar communication can have different meanings across process and maintenance states. Monitoring teams consult authorized process specialists where needed; a general IT analyst should not assume physical consequences alone. Record timestamps, source identity and collection conditions. Missing raw values constrain interpretation. This package contains no protocol parser or actual setpoints, only logical connections with purpose, direction and review reference. The exercise remains executable without becoming a production-control tool or giving learners unsupported operational instructions.
04 / EXPLANATION
Do not infer security from silence
No alert does not establish that a rule works correctly or that the plant has no incident. Review sensor coverage, intended detection behavior, retention window and authorized representative-test evidence together. Harbor distinguishes a quiet but poorly covered view from a documented view. Success is not merely a low alert count; it includes verifiable coverage and review quality. Reports state open gaps and the next needed record. Generating real test traffic or changing process behavior is outside the exercise, which uses only local synthetic evidence and produces no operational clearance.
Build the evidence yourself.
Blank workpapers are not completed tests. Fill them in your authorized environment without secrets or real personal data.
Full guide with code, outputs and reasoning ↓Primary references
Explanations are authored by SecNet. References support method and platform context; verify current editions and organizational policy for real use.