At the heart of an OT security strategy lies the ability to clearly distinguish IT and OT security. Since both share tech, operational goals, and to some extent an enabling mission, it is easy to think of them as a single entity and worse – treat their security requirements in a unified manner. Once that is out of the way viz., an asset owner or OT operator can understand the differences between OT and IT security, an entity can prepare to initiate and deploy an OT security strategy. So can one go about formulating an OT security strategy? Let’s explore the answers. To secure OT environments, we need to put in place 7 critical controls 7 critical controls for a robust OT Security posture Now let’s look at each of these in detail. 24X7 monitoring of networks and assets OT networks and assets are often left unmonitored as they are considered to be of low value to hackers or other disruptive forces. Nothing could be further from the truth. Due to a lack of basic security measures, today ICS systems and OT networks are easily accessible from outside the infrastructure. This means that these systems can easily be accessed and manipulated from outside. History has shown that accessible systems are often used by threat actors to monitor and control systems and networks of interest. Secure Remote Access for Industrial Cybersecurity What is Secure Remote Access? It broadly refers to a multitude of security measures, policies, and technologies and access methods organizations use to enable access to devices, networks and applications from a location outside of the core network in a secure manner. Organizations should be able to enable designated employees to control OT remotely in a secure manner without being impeded by protocols or compromises on functional aspects. OT Incident Response Incident response includes measures to respond to a cyber incident in a structured manner while minimizing the incident’s impact. In an OT environment, this could mean ensuring the continuity of operations, prevention of lateral movement of threats, and minimizing the blast radius, if any. In OT environments, the OT asset owners often shut down the entire OT infrastructure in response to an incident and this is a standard practice. If a structured OT Incident Response plan with clear ownership of activities, response elements and assets is put in place, not only does the quality of response improve but also the learning from each incident. It also improves the ability to recover rapidly from an incident with appropriate levels of transparency in response. Vulnerability Management in OT Security OT vulnerability management is all about ensuring all vulnerabilities are discovered well before they are exploited. This includes Zero Days and patches for all OT assets to ensure that the risk of exploitation is kept at a minimum in line with risk tolerance, best practices, OT security policies, or with compliance mandates. Suppose your enterprise can figure out attack paths I.E., the most likely way in which an asset could be exploited. In that case, it becomes easier to break that attack path either by patching a vulnerability or by adding a vulnerable asset to a DMZ or a zone. Such zones as recommended by IEC 62443 can go a long way in improving the security level not just at an asset level but also at an enterprise level. Visibility into OT risk exposure Risk exposure is a function of vulnerability management, continuous threat detection, adoption of best practices, adherence to IEC 62443 and other applicable standards, and the level of visibility that asset owners/managers have on OT assets and networks. A risk exposure score can be calculated by assigning a score to security measures and deducting numbers for every unaddressed vulnerability or risk. By knowing the enterprise risk score, asset owners can work towards improving security measures, isolating assets or networks or practices for improvement through security intervention. Critical infrastructure operators can also track the efficiency of their OT SOC and decide on the frequency of OT risk assessment and gap analysis exercises. Defensible network architecture A defensible network is monitored, managed, governed, remedied, and operated with a minimal amount of risk. A defensible network should be run with ample degree of visibility and insights into risk exposure. It should enable the adoption of security measures of the highest order and permit the deployment of relevant security measures. A defensible OT network should be segmented with a layered defense-in-depth strategy that enables additional security to be provided to crown jewels or legacy systems. A defensible network architecture that translates into robust security practices on the network can thus translate into improved risk management at the enterprise level. Additional security for crown jewels Crown jewels have to be placed insider a DMZ or a zone with additional security measures. There are many ways to achieve this including microsegmentation. With additional security, crown jewels can be shielded from cyber incidents that impact the wider network thereby lowering the unit risk exposure for vital assets. Sectrio has turnkey OT security capabilities and is today securing some of the biggest OT operators across the globe including oil refineries, airports, railway assets, manufacturing plants, ports, and power plants. We have solutions, consulting, risk assessment, services, and SOC offerings that can be customized to your unique OT security needs. Interested in learning about specific measures for protecting your crown jewels? Learn more about Sectrio’s OT security solutions Talk to us, now. Learn more about how we can be a one-stop partner for your OT security journey. Book a free consultation with our Industrial Control System security expert to learn about the latest cyber risk minimization strategies and models. Book a consultation with our ICS security experts now. Contact Us  Thinking of an ICS security training program for your employees? Talk to us for a custom package.   

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Prayukth K V

Source: Security Boulevard
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