Why Zero Trust Is Critical for IoT Security

Understanding Zero Trust: The Basics

The proliferation of IoT and OT devices across industries has dramatically expanded the attack surface, introducing complex security challenges that traditional perimeter-based models cannot address. From smart factories and healthcare devices to connected infrastructure, these devices often lack built-in security, operate on legacy systems, and connect to critical business operations, making them prime targets for cyberattackers. A zero trust architecture is essential to effectively secure this burgeoning ecosystem, ensuring that no device, user, or application is implicitly trusted, regardless of its location.

In essence, zero trust is about eliminating default trust and constantly verifying that every user, device, or service belongs in a system. Below are the core ideas that form a strong basis for network security:

• Never trust, always verify: No user or device should be considered trustworthy by default.
• Least-privileged access: Entities receive only the minimal permissions needed to complete tasks.
• Contextual and risk-based access governance: Security measures must account for a device’s context, threat level, and operational need before granting or denying access.
• Continuous monitoring and risk adaptation: Suspicious activity should prompt re-evaluation of access rights in real time, adjusting privileges as necessary.
• No public IP addresses: Exposing services directly via public IPs raises the odds of unauthorized intrusion, so they should be hidden behind secure IoT devices or proxies.

Zero Trust IoT: Why Traditional Security Fails

Modern IoT networks and their wide range of smart device deployments can create enormous attack surfaces. Because these devices often run on lightweight operating systems and have constant internet connectivity, they present lucrative targets for adversaries. A breach in one device can jeopardize network security across the entire ecosystem, leading to hijacked applications and data or interrupted operations.

Moreover, IoT settings involve complex supply chains, frequent software updates, and overlapping security systems. Without a robust zero trust approach, intruders can move laterally and subvert security postures that rely largely on perimeter-based controls. Practicing zero trust network access (ZTNA) ensures that even when attackers break through one layer, they remain isolated from other resources.

What Are the Core Principles of Zero Trust for IoT Security?

Zero trust applied to IoT security emphasizes a proactive stance toward each device and connection. By focusing on system-wide scrutiny, organizations can better protect their networks and the critical assets that rely on them:

• Dynamic device identity management: Continuously authenticate and authorize every IoT node based on verifiable credentials.
• Automated policy enforcement: Security solutions should automatically enforce rules that reduce risky connections and detect anomalies before they become threats.
• Identity-based microsegmentation and secure connectivity: Establish encrypted, identity- and context-aware connections for each device, only granting access to authorized resources.
• Isolated communication paths: Enforce logical separation between IoT devices, so unauthorized access attempts cannot spread across the entire environment.
• Continuous monitoring and anomaly detection: Continuously monitor device behavior for deviations from established baselines to rapidly identify and alert on suspicious activities that could indicate a compromise.

The Role of Segmentation in Zero Trust IoT Security

Network segmentation is one of the linchpins of a zero trust approach. By dividing infrastructure into smaller zones, it becomes possible to closely manage network traffic toward and from each IoT device. This drastically limits an attacker’s ability to move laterally across the network and compromise additional devices, effectively containing breaches and preventing incidents like ransomware propagation or data exfiltration from spreading.

Segmentation also grants access only on a need-to-have basis, effectively ring-fencing isolated parts of the IoT network. Different workloads or data sets can run independently, ensuring integrity even if one section is under siege. Through robust segmentation, organizations can scale up and confidently integrate devices without fear of catastrophic breaches.

Finally, segmentation helps preserve important distinctions between critical and less critical systems, shielding sensitive applications and data behind additional layers. Even if malicious actors breach an entry point, they encounter meaningful barriers and monitoring that discourage deeper infiltration. As zero trust evolves, segmentation remains key to defending internet of things security.

Challenges of Deploying Zero Trust in IoT Networks

Implementing zero trust in an IoT environment brings obstacles that demand careful planning. No one expects it to be effortless, but preparedness can lessen growing pains:

• Legacy devices: Older devices may lack modern firmware or operating system features, making them harder to protect.
• Resource constraints: Lightweight IoT devices often have minimal memory or computational power, limiting advanced security measures.
• Evolving threat landscape: Attackers constantly devise methods to bypass defenses, requiring ongoing vigilance and timely updates.
• Balancing security and usability: Rigid policies might hamper user experience, necessitating careful tuning to maintain productivity.

Zero Trust IoT Use Cases

Organizations across a variety of industries are successfully implementing zero trust architectures to secure their IoT deployments while enabling operational efficiency and business agility. The following real-world examples demonstrate how zero trust principles transform IoT security challenges into competitive advantages.

Manufacturing

Kubota Australia revolutionized warehouse operations by implementing zero trust connectivity for Android-based RF scanners equipped with 4G SIM cards, eliminating the need for dedicated wireless infrastructure at each location. Through Zscaler Private Access, the company's scanners securely communicate with centralized SAP ERP systems over any connection type, enabling infrastructure-less warehouses that become operational instantly.

Logistics

XPO transformed security across 300+ service centers by replacing legacy VPNs and firewalls with zero trust architecture, protecting approximately 20,000 Android handheld IoT devices used by drivers and dock workers for scanning and tracking freight. The implementation blocked over one billion threats and prevented 50 million policy violations while ensuring all IoT traffic is inspected for malware threats in both field and business environments.

Energy

MOL Group enhanced cyber resilience by routing all IoT traffic through zero trust security, including devices in smart headquarters buildings, refineries, retail networks, and data centers. The energy giant uses centralized zero trust policies to filter internet traffic from servers and IoT devices across its entire infrastructure, gaining comprehensive visibility through a single pane of glass.

How to Implement Zero Trust IoT Architecture Successfully

Although there is no one-size-fits-all approach to zero trust, certain fundamentals can markedly reinforce IoT security:

1. Conduct a thorough asset inventory: Catalog every device to understand each node’s privileges, capabilities, and role in the overall system.
2. Adopt smart segmentation: Use clearly defined zones to prevent unauthorized lateral movement within the environment.
3. Leverage context-aware policies: Base decisions on real-time data about device posture, user identity, location, and threat level.
4. Employ continuous monitoring: Keep track of network traffic and user behaviors, quickly adjusting privileges when anomalies arise.
5. Analyze user behaviors using AI and ML: Leverage artificial intelligence (AI) and machine learning (ML) see user behaviors up close and adapt to evolving IoT landscapes.
6. Implement ZTNA solutions: Deploy tools that verify every attempt to connect, ensuring only authorized entities gain access to critical resources.

By embracing these steps, organizations can secure their IoT infrastructure, keep pace with ever-evolving threats, and bolster trust in the technology that shapes our increasingly connected world.

Protect Devices with Zscaler Zero Trust IoT Security

Zscaler delivers comprehensive zero trust security for IoT and OT environments, aligning perfectly with core principles like continuous verification, least-privileged access, and dynamic segmentation to safeguard connected devices against evolving threats. 

By leveraging AI/ML-powered behavioral identity, Zscaler enables agentless discovery and classification of all IoT devices, ensuring vigilant monitoring and risk adaptation without relying on traditional perimeters or vulnerable public IPs. Our Zero Trust Exchange™ platform isolates devices into secure "networks of one" to prevent lateral movement but also provides privileged remote access with full governance, offering these key benefits:

• Comprehensive visibility: Automatically discover and classify IoT/OT devices across your organization using behavioral analysis, eliminating blind spots and maintaining real-time insight into device behaviors and risks.
• Reduced attack surface: Enforce zero trust policies to isolate compromised devices, block command-and-control communications, and prevent ransomware spread, enhancing safety for critical infrastructure.
• Simplified management: Streamline operations by replacing complex legacy tools like firewalls and VPNs with centralized, automated policy enforcement and monitoring, boosting productivity without agents or sensors.
• Business continuity: Ensure secure, fast connectivity for devices in branches, factories, and campuses, minimizing downtime and vendor risks while supporting Industry 4.0 agility.

Request a demo today to see how Zscaler can strengthen your IoT security with zero trust.