When Safety Systems Become Attack Paths

By Muhammad Ali Khan ICS/ OT Cybersecurity Specialist — AAISM | CISSP | CISA | CISM | CEH | ISO27001 LI | CHFI | CGEIT | CDCP

Cybersecurity breach in industrial systems

Introduction: The Illusion of Inviolable Safety

For decades, industrial safety systems were treated as sacred ground. They were engineered to be deterministic, isolated, and uncompromisingly conservative. Their sole purpose was to protect human life, physical assets, and the environment when control systems failed or operations drifted into dangerous territory. In traditional industrial thinking, safety systems were not only separate from control systems, but they were also conceptually untouchable from the outside world. That assumption no longer holds.

IT/OT Convergence and the Erosion of Isolation

As IT and OT environments converge, safety systems are increasingly becoming part of the same digital ecosystem they were designed to guard against. This convergence has quietly transformed safety instrumented systems from the last line of defense into potential attack paths. Modern industrial operations demand visibility, remote access, centralized monitoring, and data-driven optimization. Safety systems that were once configured locally and left untouched for years are now integrated into engineering workstations, historian platforms, asset management systems, and sometimes enterprise-level dashboards. Every new integration weakens isolation and expands the attack surface.

Connectivity as the New Threat Multiplier

Connectivity is the fundamental enabler of this shift. Firmware updates, diagnostics, compliance reporting, and lifecycle management all require digital access. Once a safety system shares a network, credentials, or trust relationship with non-safety systems, it becomes reachable in ways its original designers never anticipated. In converged environments, attackers rarely target safety systems directly. Instead, they move laterally through trusted pathways created for operational convenience, using legitimate engineering access as their entry point.

Triton: A Turning Point for Safety System Security

The Triton or Trisis malware incident in 2017 fundamentally changed how the industry perceives safety risk. Attackers deliberately targeted Schneider Electric Triconex safety controllers at a petrochemical facility, demonstrating an unprecedented understanding of safety logic, controller firmware, and engineering workflows. The intent was not disruption for its own sake, but the manipulation of safety behavior itself. The attack failed only due to a fault that caused an unexpected shutdown, exposing the presence of the malware. Triton proved that safety systems are not only attackable but strategically valuable to advanced adversaries.

Legacy Design Assumptions Under Modern Threats

Many safety systems in operation today were never designed with hostile cyber environments in mind. Authentication mechanisms are often weak, cryptographic protections may be limited or absent, and patching is constrained by operational risk. When these legacy systems are pulled into modern IT/OT architectures, the gap between assumed trust and actual threat becomes dangerous. IT teams expect rapid updates and centralized monitoring. OT teams prioritize stability and uptime. Safety engineers assume intentional manipulation is unlikely. Attackers exploit these mismatched assumptions.

Standards Warned Us, Adoption Lagged Behind

Frameworks such as IEC 62443 and NIST SP 800–82 have long emphasized segregation, secure zones and conduits, defense-in-depth, and explicit consideration of safety impacts in cybersecurity design. However, real-world implementations often fall short. Temporary network exceptions become permanent. Vendor remote access pathways are poorly governed. Monitoring tools prioritize visibility without enforcing architectural boundaries. In practice, safety systems are frequently connected in ways that technically comply with operational needs but violate the spirit of secure-by-design principles.

When Safety Systems Fail Quietly

A particularly dangerous misconception is that the primary risk to safety systems is shutdown. In reality, subtle manipulation is far more dangerous. An attacker who alters logic conditions, timing behavior, or response thresholds can leave a system operational while silently removing its protective function. Unlike a shutdown, this type of compromise can persist undetected, eroding layers of protection until a physical incident occurs. From a cyber perspective, safety systems become ideal targets precisely because their failure modes are not immediately visible.

Operational and Incident Response Consequences

When safety systems are part of the cyber attack surface, incident response changes fundamentally. A cybersecurity event becomes a potential safety event. Decisions that would normally remain within a SOC now require involvement from operations, safety engineering, and executive leadership. Containment actions must consider physical risk, not just digital impact. In converged environments, even isolating a system can have safety implications, making response slower and more complex at precisely the moment speed matters most.

Vendor Ecosystems and Transitive Risk

The growing reliance on vendors for remote diagnostics, centralized safety management, and cloud-based analytics introduces another layer of risk. A compromised vendor environment, stolen support credentials, or vulnerable update mechanisms can provide indirect access to safety systems across multiple sites. In converged architectures, safety systems may not be internet-facing, but they are often one trusted connection away from something that is. This transitive trust significantly amplifies systemic risk.

Rethinking Safety in a Converged World

The reality of IT/OT convergence is that safety and cybersecurity can no longer be managed as separate disciplines. Safety systems must be threat-modeled with the same rigor as control systems, and cybersecurity architectures must be evaluated against worst-case physical outcomes. This requires changes in governance, engineering culture, and accountability. Safety engineers must understand cyber threat models. Cybersecurity teams must understand process hazards. Architectural decisions must be judged not only by efficiency and uptime, but by their impact on resilience.

Conclusion: Defending Systems That Were Never Meant to Be Defended This Way

When safety systems become attack paths, the failure is rarely a single misconfiguration or vulnerability. It is the cumulative result of small compromises made in the name of efficiency, visibility, and modernization, without fully accounting for how trust propagates across converged environments. Safety systems do not lose their value when they are connected, but they do lose their innocence. In a world where attackers understand industrial safety as well as engineers do, defending safety systems as isolated relics is no longer realistic. Defending them as ordinary OT assets is even more dangerous.