Traditional cybersecurity measures, such as firewalls and anti-malware, were once considered adequate to protect our IT networks and industrial control systems (ICS) alike. Recently, however, this assessment has been challenged as the frequency and success of modern cyberattacks against these networks have increased. Practitioners of critical infrastructure are questioning the security tools they once used. If these technologies are repeatedly failing to protect IT networks from attack, why should they be trusted to protect control system networks? In short, which of our industrial control system networks are expendable enough to expose to these software-based, IT-style cybersecurity approaches?
The answer is, of course, “none.” None of our industrial control system networks can afford such risk. Compromised control systems put workers’ lives and public and environmental safety at risk, and introduce risks of downtime and damage to large, costly and difficult-to-replace equipment.
The damage to blast furnaces in December’s German steel mill cyberattack is a good example of these risks. This incident demonstrated what today’s attackers are capable of, and the consequences of this kind of attack. Software-based cybersecurity protections failed to protect the steel mill and the physical equipment at the site.
If not software, then what?
To provide effective protection for industrial control networks, security standards must keep pace with modern attacks. The latest NIST 800-82r2 and Agence nationale de la sécurité des systèmes d'information (ANSSI) guidance for industrial control system security recognize the strength of hardware-enforced unidirectional security gateways. Unidirectional gateways provide physical protection for control system networks, not just software security. The gateways replicate industrial servers to corporate networks, providing safe IT/OT integration for control system networks.
Given the continued evolution of best-practice ICS security guidance, and the widespread acceptance of unidirectional security gateways, the question we must all ask of our control systems networks is: which of these networks are expendable enough to be protected with only firewalls and other IT security software components?
Interested in reading about the challenges in securing IT/OT networks? Check out our recent article for more information.