ISA Unveils Top 20 Secure PLC Coding Practices for OT Cybersecurity
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ISA Unveils Top 20 Secure PLC Coding Practices for OT Cybersecurity
As ransomware groups and nation-state actors increasingly pivot from IT networks to operational technology, programmable logic controllers , the unglamorous workhorses of factory floors, water utilities, and energy grids , have become prized targets. Yet for decades, the cybersecurity community had no dedicated, vendor-neutral framework for writing secure PLC code. That gap has now closed.
Detail
The absence of PLC-specific secure coding standards has been one of the most glaring blind spots in industrial cybersecurity. While IT developers have long benefited from OWASP Top 10 and CERT secure coding guidelines, PLC programmers , who control physical processes with direct safety and environmental consequences , have operated without equivalent guidance. The Top 20 project represents a paradigm shift in closing the IT-OT security maturity gap.
and led by security experts Sarah Fluchs and Vivek Ponnada, makes a provocative and persuasive argument: the nuances of PLCs should be treated as
Unlike traditional IT software, PLCs operate in hard real-time, interface directly with physical machinery, and use specialized programming languages , ladder logic, function block diagrams, and structured text , that bear little resemblance to Python or Java. Input validation in a PLC isn't just about preventing SQL injection; it's about verifying that a pressure sensor reading is physically plausible before opening a relief valve.
, ensuring it slots directly into existing risk management and compliance workflows.
With global industrial cybersecurity spending projected to exceed $25 billion by 2028, frameworks that bridge the engineer-centric world of PLC programming with the compliance-driven world of security governance are rapidly becoming procurement differentiators. Asset owners are increasingly demanding evidence of secure coding practices in vendor RFPs.
The Top 20 Secure PLC Coding Practices trace their origin to a single session at the S4x20 conference, where
, a veteran engineer from a major water utility, shared practical tips he had accumulated over decades of making PLCs more resilient, maintainable, and secure. The session resonated so profoundly that S4 organizers elevated it into a formal community project.
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