Continuous Monitoring & Incident Management: In OT, Silence Does Not Mean Safety

Many facilities run OT with minimal security visibility. IT has EDR, SIEM, SOC workflows. OT often has none. This creates a dangerous assumption: “If there are no alarms, there is no problem.” OT attackers rely on that assumption. Many OT attacks are quiet: slow lateral movement, credential misuse, covert persistence, or subtle process manipulation.

A realistic nightmare: an attacker gets into OT but does nothing disruptive at first. They observe traffic, learn how HMIs communicate with PLCs, understand command patterns, and map the process. Then they issue commands that look “normal” but shift parameters over time. Without logs, network detection, time synchronization, and session recording, you may not notice for weeks. During that time, you suffer quality loss and maintenance cost increases, with no clear explanation.

OT monitoring typically has two layers:

1. Network-based detection (NDR/IDS): sensors that understand OT protocols and flag anomalies.

2. Log collection and correlation: jump host logs, firewall logs, identity events, SCADA/historian logs, remote access records.

Even a baseline incident management capability dramatically improves outcomes:

• Who connected, when, and from where?

• Are there unexpected inter-zone flows?

• Did a new device appear on the network?

• Did PLC logic change?

• Were HMI/SCADA configurations modified?

• Are there repeated authentication failures or unusual remote sessions?

A mature OT incident workflow avoids panic-driven “shortcuts” (disabling firewalls, opening wide RDP). Instead, it runs a controlled playbook:

• Contain: isolate the affected zone/conduit, preserve continuity elsewhere.

• Collect evidence: logs, packet captures, session recordings, system snapshots.

• Recover: restore using DR runbooks and validated golden images.

• Root cause: identify entry vector and persistence mechanism.

• Harden: close access gaps, tighten segmentation, enforce MFA, patch where feasible.

The business case is simple: without monitoring, security is guesswork. With monitoring, you can measure, detect early, and respond before the impact becomes catastrophic. OT security is rarely about “perfect prevention.” It’s about early detection and controlled response to minimize downtime and safety risk.