Zero Trust in Production: Why the Firewall Alone Is No Longer Enough

Zero Trust in Production: Why the Firewall Alone Is No Longer Enough

For decades, the security strategy in industry was clearly defined: A strong “moat” (the perimeter firewall) protects the internal machine network from the outside world. But in the connected Industry 4.0, this model is crumbling. Once malware—such as through an infected technician’s laptop or a compromised remote maintenance interface—enters the internal network, it often has free rein. This is where the Zero Trust model comes in. The principle: “Trust no one, verify everyone.” Learn how micro-segmentation within Kubernetes prevents a small incident from becoming a fatal production halt. The problem: The risk of lateral movement In traditional, “flat” networks, compromised systems can communicate freely with other devices in the same segment. Hackers exploit this for so-called lateral movement: They jump from a less critical system (e.g., a display panel) to the central controls of the production line. The dangers of flat network structures:

• Domino effect: A single infected sensor can cripple an entire factory hall.
• Lack of visibility: Within the firewall, data traffic (“East-West traffic”) often goes completely unmonitored.
• Outdated protocols: Many PLC controls have no security mechanisms of their own and rely blindly on network protection. The solution: Micro-segmentation with Kubernetes

Instead of relying on a single large wall at the outer boundary, we use Kubernetes to draw many small partitions directly around individual applications. This is what we call micro-segmentation.

1. Network Policies: The Digital Firebreak

Within the cluster, we use Network Policies. By default, all communication is forbidden (Default Deny). We explicitly allow only the connections that are absolutely necessary for operation.

• Example: An analytics container may read data from the PLC but must never send commands to the ERP system.

2. Isolation at the Namespace Level

Through logical separation into “Namespaces,” different production areas (e.g., Assembly Line A and Paint Shop B) can be isolated as if they were running on completely different hardware—even though they use the same cluster.

3. Identity-Based Security

In the Zero Trust model, it’s no longer about the IP address but the identity. Each application in the cluster receives its own certificate. Before data flows, services authenticate each other (Mutual TLS). An attacker who merely spoofs an IP address fails due to the lack of cryptographic identity. Why Zero Trust protects OT availability

OT decision-makers often fear that more security will slow down production. With Zero Trust, the opposite is true:

• Containment instead of shutdown: If malware infects a segment, it is isolated there. The rest of the production continues unaffected.
• Secure remote maintenance: External partners only get access to the specific container they need to maintain—not the entire network.

Compliance (NIS2): Micro-segmentation is a core component to technically demonstrably implement the strict requirements of modern cybersecurity guidelines.

Conclusion: Security Directly at the Workload

The firewall at the network boundary remains important, but it is no longer enough. True resilience in the smart factory only arises when security is implemented directly where the data is generated: in the cluster, between the containers, following the Zero Trust principle. This not only makes your production more digital but also impervious to the domino effect of modern cyberattacks.

FAQ – Strategic Short Info

What is Lateral Movement in Production?

Lateral Movement describes the lateral spread of an attacker or malware within a network after the outer protective wall (firewall) has already been breached.

How does Kubernetes prevent the spread of malware?

Through the use of Network Policies and micro-segmentation. These ensure that applications can only communicate with explicitly authorized partners. All other connection attempts are automatically blocked.

What does “Default Deny” mean in the Zero Trust context?

“Default Deny” is a security configuration where all network traffic is fundamentally prohibited. Communication for necessary processes is only enabled through explicit rules.