On a July morning in 2021, operations at South Africa’s busiest port ground to a halt. Transnet confirmed a cyber “disruption” that delayed shipments and rippled through the wider economy. While the public impact was immediately visible, cybersecurity specialists were more concerned about what lay beneath: the growing exposure of operational technology alongside traditional IT systems.
This was hardly an isolated case. From the Stuxnet attack on Iranian centrifuges to the Ukraine power grid cyberattack, cyber incidents have moved beyond stolen data and locked laptops. When OT is affected, the consequences can include halted production, damaged equipment, safety incidents, and environmental risk.
As South Africa continues to rely on energy, mining, transport and utilities to drive growth, the intersection between IT and OT security has become one of the most important engineering challenges of the decade.
IT and OT: same objective, very different environments
At a high level, IT and OT security aim to manage risk and ensure continuity. In practice, they operate under very different constraints.
IT systems are designed with data protection and business continuity in mind. They are patched regularly, refreshed often, and built with interoperability in mind. Downtime, while undesirable, is usually manageable if backups exist.
OT systems exist to keep physical processes running safely and predictably. They include PLCs, SCADA systems, distributed control systems and field devices that may remain in service for decades. In many cases, downtime is simply not an option. A failed update or unexpected reboot can mean damaged equipment, environmental spills, or serious injury.
As industrial systems have become more connected through IIoT platforms, remote diagnostics and enterprise integration, these two worlds now sit side by side. That proximity has created opportunity, but it has also created risk. A compromised email server or misconfigured firewall can become the first step into a control network that was never designed to defend itself.
Lessons from real-world incidents
Several high-profile events illustrate how OT attacks differ from traditional IT breaches.
- Stuxnet (2010) demonstrated that malware can be engineered to manipulate physical processes while feeding operators false feedback. The damage occurred inside the process itself.
- The Ukraine power grid attack (2015) showed how remote access to substations could be used to cause immediate, large-scale outages.
- The Transnet port disruption (2021) highlighted how logistics systems with mixed IT and OT dependencies can impact national trade when compromised.
Across all three incidents, the impact reached far beyond the server room.
Why OT environments remain vulnerable
OT systems carry several structural weaknesses that attackers increasingly exploit.
Legacy protocols such as Modbus, Profibus and DNP3 were built for trusted, isolated networks. Encryption and authentication were never part of the design.
Patch constraints are also real. Updating a PLC that controls a mine hoist or water pump may require production shutdowns and specialist vendor support, leaving known vulnerabilities unaddressed for years.
Expanded remote access through VPNs, cloud dashboards and remote desktop tools increases convenience, but also enlarges the attack surface.
Limited visibility remains a major issue. Many organisations have strong IT monitoring but little awareness of what “normal” looks like inside OT traffic.
Skills gaps persist. IT security teams may lack process knowledge, while engineers may not be trained to recognise cyber threats. The handover between the two is where risk often hides.
Engineering security into OT systems
For engineers, OT security works best when it is treated as a design discipline rather than an afterthought.
Key practices include clear asset inventories, strong network segmentation between IT and OT environments, and disciplined access control. Where modern, secure protocols are available, they should be used. Where they are not, compensating controls such as protocol gateways, VPN encapsulation and continuous monitoring become essential.
Fail-safe behaviour is equally important. When systems are disrupted, they should default to safe states and local control, rather than uncontrolled shutdown or unpredictable behaviour. In OT environments, resilience is as much about physics as it is about software.
Preemptive standards and frameworks
Several international frameworks now provide practical guidance for securing industrial environments.
IEC 62443 defines a structured approach to OT security across system design, implementation and operation.
NIST SP 800-82 offers detailed guidance on securing industrial control systems.
ISA and IEC standards continue to shape best practice across the OT lifecycle.
In South Africa, the regulatory environment is still evolving, but expectations are changing. Insurers, lenders and regulators increasingly expect operators of critical infrastructure to demonstrate alignment with these global benchmarks.
Aligning IT and OT security priorities
Technology alone will not solve the problem. The more difficult work is cultural.
IT teams are trained to prioritise confidentiality and rapid patching. OT teams are focused on uptime, safety and predictable behaviour. Sustainable security requires both perspectives to coexist.
Joint governance structures, shared incident response planning and cross-disciplinary training help close the gap. When engineers and security teams plan together, organisations gain resilience without sacrificing operational stability.
What lies ahead for OT security
Several trends are shaping the next phase of OT protection.
AI-assisted anomaly detection is improving visibility into industrial networks. Digital twins are increasingly used to test cyber scenarios without risking live operations. Zero-trust concepts are being adapted for OT environments, with tighter access control and continuous verification.
Collaboration across industries is also gaining momentum. Threats faced by mining, energy and manufacturing sectors often overlap, and shared intelligence is becoming a practical defence mechanism.
Securing the systems that keep the country running
Operational technology supports almost every critical service in South Africa, from electricity and water to transport and mining. As these systems become more connected, they inevitably become more exposed.
For engineers, cybersecurity now sits squarely within the systems engineering remit. Protecting OT is fundamental to safety, reliability and national resilience.
The Transnet incident was a warning. With thoughtful design, disciplined governance and closer coordination between IT and OT teams, it does not have to become the norm.
