Industrial IoT Security FAQ

The biggest Industrial IoT security risks include:

• Legacy devices with no security features
• Default or weak credentials
• Flat network architectures without segmentation
• Unpatched and outdated firmware
• Insecure remote access
• Lack of encryption for data in transit
• Insufficient monitoring and logging
• Poor physical security

The convergence of IT and OT environments creates additional risks as previously isolated industrial systems become connected to enterprise networks and the internet.

Learn more: Securing Industrial IoT Deployments

OT/IT convergence refers to the integration of operational technology (industrial control systems) with information technology (business systems). Security implications include:

• Expanded attack surface as previously isolated systems connect to networks
• Different security cultures and priorities between OT and IT teams
• Legacy OT systems not designed for current threats
• Need for new tools that understand both environments
• Organizational challenges in defining responsibilities

Successful convergence requires collaboration between IT and OT teams with shared security goals.

Secure IIoT devices through:

• Changing default credentials immediately
• Implementing strong authentication
• Keeping firmware updated
• Disabling unnecessary services and ports
• Using encrypted communications (TLS/SSL)
• Placing devices on segmented networks
• Implementing access controls
• Monitoring for anomalies

For legacy devices that can't be secured directly, use network segmentation and industrial firewalls to isolate them. Follow the principle of least privilege—devices should only have access to what they need.

Network segmentation divides networks into separate zones with controlled access between them. For IIoT, this typically means separating OT networks (production systems) from IT networks (business systems) with a DMZ in between.

Segmentation provides:

• Limited blast radius: If one zone is compromised, others remain protected
• Policy flexibility: Different security policies for different zones
• Better visibility: Clearer view of network traffic between zones

The Purdue Model is a common reference architecture for industrial network segmentation.

The Purdue Model is a reference architecture for industrial control system networks, defining five levels:

• Level 0: Field devices and sensors
• Level 1: Basic control (PLCs, RTUs)
• Level 2: Area supervisory control (HMIs, engineering workstations)
• Level 3: Site operations (historians, MES)
• Levels 4-5: Enterprise (ERP, business systems)

A Demilitarized Zone (DMZ) sits between Level 3 and Level 4. The model guides network segmentation by defining which systems should communicate directly and where security boundaries should exist. Modern IIoT often requires adapting the Purdue Model for cloud connectivity.

For IIoT, implement encryption at multiple levels:

• Data in transit: TLS 1.2 or higher
• Data at rest: AES-256
• Device identity: Certificate-based authentication
• Remote access: VPNs with strong encryption

For resource-constrained devices, consider lightweight cryptographic protocols designed for IoT. Ensure certificates are properly managed with rotation policies. Cloud connections should use mutual TLS (mTLS) where possible. Don't use deprecated protocols like SSL or TLS 1.0/1.1.

Secure remote access through:

• VPNs with strong authentication (preferably multi-factor)
• Jump servers that provide controlled access points
• Session recording and monitoring
• Time-limited access with approval workflows
• Principle of least privilege (minimum necessary access)
• Separate credentials from regular user accounts
• Regular access reviews

Avoid direct remote access to control systems—route through secure intermediate servers. Consider zero-trust architectures that verify every access attempt regardless of network location.

Legacy equipment often can't be patched or upgraded, requiring compensating controls:

• Isolate legacy systems on separate network segments
• Use industrial firewalls with application-aware filtering
• Implement intrusion detection systems
• Monitor network traffic for anomalies
• Restrict physical and remote access
• Use jump servers for any required connectivity
• Document and assess risks
• Plan for eventual replacement

The goal is to reduce attack surface while maintaining required functionality.

Industrial security patching requires balancing security with operational continuity:

• Establish a patch management policy and process
• Maintain an accurate asset inventory
• Prioritize patches based on risk and criticality
• Test patches in non-production environments first
• Schedule patching during planned maintenance windows
• Have rollback plans for failed patches
• Use compensating controls when patching isn't possible
• Document exceptions with risk acceptance

Work with vendors to understand patch testing and support timelines.

IEC 62443 is the international standard series for industrial automation and control systems (IACS) security. It provides a framework for implementing cybersecurity across industrial systems, covering:

• Product development security
• System integration requirements
• Operations and maintenance

The standard defines security levels and provides requirements for vendors, integrators, and asset owners. Using IEC 62443 helps ensure comprehensive security coverage, provides a common language with vendors, and may be required for certain industries or contracts.

Learn more: Safety and Compliance Topic Hub

Look for vendors with:

• IEC 62443: Certification for products and development processes
• SOC 2 Type II: For cloud services
• ISO 27001: For security management systems
• Industry-specific certifications: Where applicable

Evaluate vendor security practices through questionnaires and audits. Check for responsible disclosure programs and track record of timely security patches. For critical systems, consider third-party penetration testing of vendor solutions.

Effective IIoT security monitoring includes:

• Network traffic analysis for anomaly detection
• Log collection and SIEM integration
• Intrusion detection systems (IDS) with industrial protocol support
• Asset inventory and vulnerability scanning
• User and device authentication logging
• Alerting on policy violations
• Regular security assessments

Use OT-specific security tools that understand industrial protocols. Baseline normal behavior to detect deviations. Integrate IT and OT security monitoring for comprehensive visibility.