Polymer production plants increasingly rely on connected systems to monitor processes, exchange production data, and support remote troubleshooting.
Process-control environments may communicate with business networks, historian platforms, monitoring tools, and approved remote-access services. Each connection creates operational value, but it can also create a path into systems that affect production.
Operational technology requires a different security approach from standard corporate IT. As the NIST Guide to Operational Technology Security explains, OT systems must be secured without losing sight of their performance, reliability, and safety requirements.
An office-network incident may disrupt communications or business applications. An incident involving a programmable logic controller, distributed control system, or SCADA environment can affect production availability, equipment, and worker safety.
The goal is to reduce exposure while protecting operational continuity.
Key Takeaways
- Map every connection between operational technology and business systems.
- Segment OT networks based on operational risk and required data flows.
- Restrict remote access through monitored, approved pathways.
- Maintain an accurate OT asset inventory and a risk-based patching process.
- Test incident-response procedures with operations, IT, and safety teams.
Map OT and IT Connections
Before implementing new controls, identify where operational technology meets information technology and document what crosses that boundary.
Depending on the facility, OT systems may include distributed control systems, PLCs, SCADA components, HMIs, historian platforms, smart sensors, and environmental or safety-related systems. IT systems may include email, ERP platforms, corporate applications, and general business traffic.
Document the systems on both sides of the boundary, the data moving between them, and the users or services authorized to cross it. Where relevant, record the industrial protocols in use, such as Modbus, PROFINET, EtherNet/IP, or OPC UA.
Our ICS cybersecurity guide for manufacturers explains why visibility into control systems, connected devices, and remote-access pathways is an essential starting point for industrial security.
This map should remain current as integrations, vendors, and production systems change.
Segment the Network Based on Operational Risk
After mapping the environment, separate OT and IT networks so that only approved traffic can move between them.
Use firewall rules and, where appropriate, an industrial demilitarized zone to limit connections. For example, a historian service that needs process data should receive only the access required for that function. It should not create a broad pathway into the control environment.
Segmentation also matters within OT. Production areas and critical systems should not share unrestricted network paths when that access is unnecessary. Separating systems by function and risk level can reduce the impact of a compromised workstation, vendor account, or connected device.
Restrict Remote Access
Remote access can support diagnostics, maintenance, and multi-site operations. It can also create unnecessary exposure when permissions are broad, permanent, or poorly monitored.
Use a dedicated, monitored access path for production systems. Avoid giving users unrestricted access to the OT environment simply because they have VPN credentials. Limit each account to the systems required for an approved task.
CISA’s secure connectivity principles for OT provide a useful framework for managing connections into operational environments.
Strengthen remote access by:
- Requiring multi-factor authentication.
- Logging sessions and reviewing unusual activity.
- Enabling vendor access only during approved maintenance windows.
- Removing inactive accounts and outdated permissions.
- Reviewing accounts, permissions, and logs on a defined schedule based on risk.
Plan Patching Around Production
Patch management in OT environments requires coordination. Some updates need testing before deployment. Others must be scheduled around planned maintenance windows to avoid unnecessary production disruption.
Create a risk-based patching process that identifies:
- Systems exposed to remote access or business-network traffic.
- Devices running unsupported software or firmware.
- Updates that require vendor validation.
- Systems that cannot be patched without operational changes.
- Compensating controls for legacy equipment.
When immediate patching is not feasible, reduce exposure through segmentation, restricted access, application allowlisting where appropriate, and additional monitoring.
Maintain an Accurate OT Asset Inventory
A plant cannot manage risks it cannot see. Maintain an inventory of connected OT devices, including PLCs, HMIs, engineering workstations, sensors, network equipment, and supporting systems.
For each asset, document:
- Device type and manufacturer.
- Network address.
- Firmware or software version.
- Communication protocols.
- Operational owner.
- Production function.
- Support status and patch requirements.
The CISA asset-inventory guidance for OT owners and operators outlines how organizations can identify, classify, document, and maintain visibility into operational assets.
Passive OT-monitoring tools can also help identify devices and changes without relying solely on manual records. Use the inventory to guide segmentation, patching, replacement planning, and incident response.
Monitor OT Network Traffic
Industrial environments often follow recognizable communication patterns. Changes in destinations, protocols, or connection behavior may signal a configuration issue, unauthorized access, or another security concern.
OT-aware monitoring tools can passively observe network activity and help teams identify anomalies. General-purpose IT tools may still provide useful information, but they may not offer the same visibility into industrial protocols or process behavior.
Assign clear responsibility for reviewing alerts and escalating issues. When the internal team does not have OT-specific capacity, a co-managed security partner can provide additional monitoring and response support.
For a broader look at this risk, read our guide to OT security in manufacturing.
Secure Physical Network Access
Network security also depends on physical access.
Place network equipment in controlled areas or locked enclosures where appropriate. Disable unused ports. Use enterprise authentication for wireless access points and separate guest or contractor access from production systems.
Contractors who need connectivity for maintenance or commissioning should receive only the access required for the approved work. Remove that access when the engagement ends.
Test the OT Incident-Response Plan
A production-system incident requires coordination across operations, IT, and safety teams. The response plan should account for operational consequences, not only technical recovery.
Document:
- Who can authorize system isolation?
- Which systems are critical to safe operations?
- How production may be affected during containment.
- How vendor access will be reviewed.
- How systems will be validated before returning to service.
- How teams will communicate during the incident.
Run tabletop exercises using realistic scenarios, such as ransomware, unauthorized remote access, or a compromised vendor connection. These exercises help teams identify gaps before an incident affects production.
Start With a Structured Security Assessment
OT security is not a one-time project. It requires clear ownership, current documentation, risk-based priorities, and regular review as systems and integrations change.
At Keystone Technology Consultants, we help manufacturers across Northeast Ohio assess OT and IT security risks, strengthen access controls, improve visibility, and build practical security plans around production requirements.
A structured review can help your team identify the highest-priority gaps and decide what to address first.
