As IT and OT systems increasingly interconnect, the convergence exposes OT systems—comprising industrial equipment, processes, and critical infrastructure in manufacturing, power generation, energy transportation, and more—to heightened cyber attack risks.
Once removed from isolation and exposed to the same risks as traditional IT systems, OT systems demand a unique approach to security. In an environment where availability, safety, and low-latency real-time functionality are the primary focus areas, a risk assessment must consider all three.
Below are 15 key recommendations for the protection of OT systems against cyber attacks and building resilience in an ever-changing threat landscape.
1. Conduct regular risk assessments
Understanding the specific vulnerabilities and risks that exist in your environment is the basis of an effective OT cybersecurity strategy. Periodic risk assessments might help point out weaknesses in your system, determine the potential impact of cyber attacks, and draw out areas where improvements are most warranted. Incorporating industrial cyber security solutions as part of these risk assessments can further enhance your ability to address vulnerabilities effectively.
Moreover, because OT systems pose both cybersecurity risks and physical safety hazards, OT system risk assessments must be tailored to both cybersecurity and physical safety hazards.
2. Distinguish IT and OT Networks
Although IT and OT systems sometimes need to communicate with each other, they should never be on the same network. Network segregation from the IT environment, taken to a robust point, will limit the further spread of malware or ransomware from one system to another.
Use firewalls and other security controls to establish secure zones that shield OT systems from threats targeting IT networks.
3. Apply Strong Access Control
Limiting access to OT systems is the most significant step in securing them against unauthorized users. Access controls aim to allow only authorized employees to access the OT systems and sensitive areas, often through multi-factor authentication, role-based access control, really tough password policies, etc.
Privilege limitation, also known as the principle of least privilege, aims at limiting privileges to only what is needed for users to perform their work.
4. Keep OT Systems Up-to-Date
Outdated software and hardware in OT systems may provide known security exploit vulnerabilities. However, patching OT systems is often more challenging than for IT systems since unplanned and unwanted downtime can endanger critical operations.
Maintain a regular patch management program that ensures minimum disruption to operations without missing a beat in addressing vulnerabilities. Where the application of patches cannot be undertaken immediately, consider virtual patching or compensating controls until patches can be successfully applied.
5. Use Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS)
IDS and IPS technologies in OT environments can detect and block real-time malicious activities. These systems log network traffic and report odd behavior, such as unauthorized access attempts or anomalous activity.
Since OT systems call for high levels of availability, very typical IDS and IPS solutions tailored to OT environments must be conducted to avoid the disruption of normal operations while enhancing security.
6. Train Employees Regularly on OT Security
Human error accounts for the majority of cyber breaches. Employees who frequently access OT must be educated on best cybersecurity practices. They should be taught how to identify phishing emails and identify peculiar behavior, among other things.
They must be enlightened about the types of risks specific to the OT systems of an organization. This kind of awareness prevents several such successful attacks at the organizational level.
7. Implement Network Monitoring and Anomaly Detection
Network monitoring activities are essential to recognize such possible cyber threats at an early stage. Systems using machine learning and artificial intelligence will identify anomalies and their deviation from normal network behaviors, signifying possible cyber threats.
For an OT environment, such systems will be early in catching malicious activities and are invaluable since it is with the immense need for effective responses to emerging threats.
8. Leverage Secure Remote Access Solutions
Now, remote access to OT systems creates a huge security risk considering that most workers are more accustomed to working remotely.
To minimize this risk, make sure you put in place secure remote access solutions, such as virtual private networks or secure tunnels, and the access shall be configured only for a few who need it and strictly control this through multi-factor authentication, encryption, and session monitoring.
9. Vulnerability Scanning and Penetration Testing
Continuous vulnerability scanning and penetration testing are effective ways of finding weaknesses in OT systems that can be exploited by hackers. Vulnerability scanning might be automated but is still aimed at periodic checks for known vulnerabilities.
Penetration testing, in many respects, mimics hackers trying to breach the system with a view to identifying any potential weakness in the security posture of the system. This is paramount for continuous improvement in the security posture of OT systems.
10. Develop OT System-specific Incident Response Plans
An IRP is a necessary element of any cybersecurity plan. For OT systems, the plan should focus specifically on the risks and operational environments in industry settings.
An IRP addresses procedures for isolating affected systems, minimizing downtime, and restoring functionality safely and efficiently. Hold regular drills and simulations in which all stakeholders are ready to move quickly in an incident.
11. Implement Physical Security Controls
OT system cybersecurity is not only about digital threats. In addition, the physical security aspect must also be addressed. Inexperienced or uncontrolled access may lead to manipulation or disruption of critical processes from OT systems.
Robust control of physical security measures must include controlled access to facilities, CCTV surveillance cameras, and security personnel in place to minimize the risk of insider threats and physical sabotage.
12. Encrypt Data in Transit and at Rest
The data exchanged between OT systems or stored within these systems must be encrypted as a best practice. Encryption assures that even if the data is intercepted or exfiltrated for analysis, it will still not be available or usable to the attackers. Encryption for both, data in transit and at rest can ensure good defense against data breaches and safeguard crucial information.
13. Role-Based Access for Vendors and Third Parties
For many OT systems, this means depending on third-party vendors that are used for maintenance and software updates or on some specialized equipment. Using vendors to access systems usually increases their cybersecurity risks.
14. Industry-Specific Security Standards Compliance
Today, most OT-intensive industries are ruled by specific cybersecurity regulations and standards. For instance, the energy industry must adhere to NERC CIP, whereas manufacturing must adhere to ISO/IEC 27001.
Your OT systems should always be in line with all regulatory requirements and standards to avoid penalties and loss of security.
15. Backup of Critical Systems and Data periodically
Regular back-ups are, therefore, very vital for the recovery of such cyber attacks, especially ransomware attacks.
There should be comprehensive backup strategies whose purpose is to ensure critical data and system configurations are backed up regularly and then stored in secure offsite locations for OT systems. These should be tested regularly to confirm easy and trouble-free restoration in the event of an attack.
Conclusion
OT systems need to be protected against cyber-attacks through a multi-layered approach that provides mitigation against digital and physical risks.
From the above recommendations, applying them should make organizations better equipped to protect and maintain critical infrastructure, ensure operational continuation, and keep costly and interruptive cyber incidents at bay.
With this threat continuously changing, such proactive measures, regular assessments, and continuous employee training are some of the things needed to maintain security in the OT environment.
FAQs
- What is the key challenge in securing OT systems?
The key challenge is to balance cybersecurity with the requirement for continuous operation and minimal downtime.
- Why is network segmentation an important aspect of OT security?
Network segmentation limits the spread of cyber attacks by isolating critical OT systems from IT networks and potential threats.
- How often should OT systems be secured?
OT systems should be secured regularly—at least once a year or whenever major changes occur in the network or infrastructure.