Under the wave of Industry 4.0 and smart manufacturing, factory operation technology networks have become the core of the production system. Different from traditional enterprise information technology networks in the past, OT networks directly control physical equipment and production processes. Its security is directly related to personnel safety, environmental safety and production continuity. Once a network attack occurs, it may cause the entire production line to stop running, cause equipment damage, or even cause a security incident, which will cause huge economic losses and reputational impact. Therefore, building an OT network security system with defense-in-depth characteristics is a very serious and difficult challenge that every modern factory must face.
Why OT cybersecurity is different from traditional IT security
The key task of the OT network is to ensure the real-time nature of the production process, as well as reliability and security. This is fundamentally different from the IT network that regards data processing and confidentiality as its core. The general life cycle of OT equipment can last for decades. Many old systems did not take network security into consideration at the beginning of the design, and neither can install modern anti-virus Software cannot be patched frequently; in addition, the consequences of an OT network interruption are immediate and physical. Even a short outage is likely to mean millions of losses, which is incomparable to the impact of a short interruption to an IT system.
Among the priorities of OT security, "availability" ranks first, followed by integrity and confidentiality. No safety measures can be taken at the expense of the stable operation of the production process. For example, in an OT environment, blindly carrying out vulnerability scanning may directly cause sensitive PLC controllers to crash. Therefore, it is dangerous and ineffective to directly apply IT security products and strategies to the OT environment. Security solutions and governance processes specifically designed for industrial environments must be adopted.
How to identify common vulnerabilities in factory OT networks
There are loopholes in the factory OT network. These loopholes are ubiquitous and of various types. Among them, the most common ones are vulnerabilities caused by old systems. Many PLC, DCS and SCADA systems are still using operating systems like XP that are no longer supported, and there are a large number of unpatched vulnerabilities. Secondly, the network boundary is blurred. In order to achieve data interaction between IT and OT, the "air gap" that was originally in a state of physical isolation is broken. However, there is a lack of strict access control, which allows attackers to move laterally from the IT network to the OT network.
Another common vulnerability comes from the supply chain and third-party maintenance. Equipment suppliers, system integrators, and maintenance personnel generally have remote access rights. However, the security of these channels is often weak, lacking multi-factor authentication and session monitoring, and the abuse of mobile storage devices such as USB flash drives in OT environments has become the main way for viruses to spread. Systematic identification of these vulnerabilities requires a combination of asset discovery, vulnerability assessment, network traffic analysis and other means.
What key technologies are needed for factory OT network security?
For network security in factory OT, the key technologies mainly include next-generation industrial firewalls. This firewall can deeply analyze industrial protocols and achieve precise management and control of TCP, OPC UA, and other protocols. Based on the "whitelist" policy, only authorized instructions and access are allowed, and any abnormal operations are blocked. The second is the industrial intrusion detection system. This system uses passive traffic monitoring to learn normal communication patterns and can detect malicious attacks and abnormal behaviors targeting industrial protocols in real time.
A security monitoring and situational awareness platform that can centrally collect logs and alarms from firewalls, IDS and various industrial control equipment and present the security situation of the entire OT network through correlation analysis. It is a core technology. Technologies such as application whitelists and one-way security gateways also play an important role in specific scenarios. These technologies together form an active defense system for the OT network and can provide services to those with weak needs!
How to establish an effective OT security management system
Technology is just a tool. If there is no complete management system to support it, the safety effect will be greatly reduced and compromised. To establish an OT security management system that can produce results, you must first clarify where the responsibility belongs. You must establish a person in charge of OT security and form such a joint security team. This team is jointly participated by IT, OT, and operations departments. Secondly, a set of specialized OT security policies and standards need to be developed, which cover access control, patch management that exists here, remote access, physical security and incident response, etc. in various scenarios.
What is particularly critical is that regular security awareness training must be carried out for production line engineers and equipment maintenance personnel. They must understand basic network security principles, such as not plugging in and out of unknown U disks casually, not clicking on suspicious emails, etc. At the same time, an emergency response plan for OT security incidents must be constructed and regularly practiced to ensure that when a security incident occurs, the operations team and security team can quickly collaborate and handle it appropriately in accordance with the established procedures to minimize losses.
How to conduct OT network security risk assessment
There is a process that belongs to OT network security risk assessment and is systematic. Its purpose is to identify threats, discover vulnerabilities, and quantify potential business impacts. The first step in assessment is asset discovery, which also includes asset inventory. It is not only necessary to identify all of them, such as controllers, HMIs, historical servers, etc., but also to clarify the key business processes they carry and the data flows between them. If you don't understand your assets, you can't carry out a risk assessment.
The next step is to carry out threat modeling and vulnerability analysis. From the attacker's perspective, possible attack paths must be analyzed, just like launching an intrusion into the controller from the office network with the help of an engineering station. At the same time, vulnerability scanning tools and manual configuration inspections must be combined to find out the security weaknesses in the system. Finally, risks are rated based on the importance of assets, the likelihood of threats occurring, and the severity of the vulnerability. This provides a basis for decision-making for subsequent security investments and rectification measures.
What is the emergency response process for OT security incidents?
When an OT security incident occurs, a clear and efficient emergency response process is the key to mitigating losses. The first step is to conduct detection and confirmation. With the help of monitoring alarms or operator reports, a preliminary judgment is made as to whether a security incident has occurred, and the emergency response team is immediately activated. The second step is to implement containment, prioritizing isolation measures that do not affect production, such as disconnecting individual damaged workstations from the network rather than shutting down the entire production line.
Entering the eradication and recovery phase, after containing the situation, you must completely remove the attacker's access rights, such as resetting passwords, patching vulnerabilities, and restoring the system from clean backups. The post-event summary is the last item. It is necessary to analyze the root cause of the incident in detail, evaluate the effectiveness of the response process, and improve safety protection measures and emergency plans based on these. Throughout the entire process, it is very important to maintain transparent communication with management and relevant departments.
In your factory, how do you balance production efficiency and OT network security requirements? What do you think is the biggest challenge right now? Please share your opinions in the comment area. If this article is helpful to you, please feel free to like and forward it.
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