Common OT Security Problems

Flat OT Networks

Many industrial environments evolve into flat operational technology networks with limited segmentation, unclear trust boundaries, and uncontrolled communications between systems.

Overview

Flat OT networks are common within legacy industrial environments where systems have expanded over time without a defined security architecture.

Engineering workstations, HMIs, PLCs, historians, vendor access solutions, and operational servers may all communicate across shared switching infrastructure with limited segmentation or traffic control.

This increases the potential impact of faults, unauthorised access, malware propagation, misconfiguration, and lateral movement across operational systems.

Typical impact

Typical impact
  • increased lateral movement risk
  • poor separation between critical systems
  • difficult firewall implementation
  • limited asset visibility
  • weak audit evidence
How Meridian helps

We review existing architectures, define zones and conduits, and produce practical segmentation recommendations suitable for brownfield and live industrial environments.

Further detail

Flat OT architectures often develop gradually through project modifications, temporary connections becoming permanent, unmanaged switch deployment, or historic operational decisions made before modern OT cybersecurity requirements existed.

Typical Indicators
  • Large shared Layer 2 operational networks
  • Limited or absent security zoning
  • Shared switches between unrelated systems
  • Minimal traffic filtering between operational assets
  • Engineering laptops connected directly into control networks
  • Poor visibility of system-to-system communications
  • Vendor remote access without clear segmentation
  • Legacy infrastructure with unclear ownership

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Placeholder image showing a simplified flat OT network architecture

Placeholder – Flat OT network architecture overview graphic

Discuss flat ot networks

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