By Dan Behrens and Daniel Pare
Organizations in industrial sectors depend on secure, stable networks to maintain operational uptime and efficiency. In these environments, downtime can result in severe consequences, including safety risks, regulatory noncompliance, and financial losses that can range from thousands to hundreds of thousands of dollars per minute. To address these challenges, companies continuously invest in improving plant efficiency and uptime, placing greater emphasis on robust operational data and interconnected systems. However, this growing connectivity introduces heightened security risks, underscoring the need for tailored OT security solutions.
The evolution of industrial connectivity has brought significant changes since Ethernet replaced older serial field bus systems. These early systems were designed for localized communication and control, with little thought given to broader network connectivity or security. As organizations embraced connected systems to improve efficiency and data flow, new risks began to surface. Many industrial networks remain flat, with minimal segmentation, making them easier for attackers to exploit once access is gained.
Adding to these challenges, industrial equipment is often deployed for decades, which introduces complexity in maintenance and security. Hardware updates and software patches are frequently delayed to prevent production disruptions, and typically require lengthy validation cycles. Vendors may release updates sporadically, and the limited availability of maintenance windows further complicates timely updates. As a result, outdated and vulnerable systems often remain in production environments, significantly increasing the vulnerable attack surface within industrial environments.
Securing an industrial environment starts with a thorough understanding of assets and their relationships. Visibility into these assets is essential for accurately assessing risks and implementing effective security policies. Traditionally, organizations relied on spreadsheets or disconnected systems to manage asset inventories. However, these methods often became outdated due to changes such as mergers, acquisitions, or operational shifts, resulting in incomplete or inaccurate information.
Modern, network-based discovery mechanisms are designed to fill these gaps by automatically identifying deployed assets within a network. Unlike traditional IT discovery tools like network scanners, which can disrupt sensitive OT devices and cause unplanned downtime, OT-focused solutions are built to operate safely within industrial environments leveraging discovery techniques native to ICS protocols. These solutions can identify assets, map communication patterns, and detect vulnerabilities without interfering with critical operations, enabling organizations to maintain both security and productivity.
Passive discovery is a key method for identifying industrial assets by monitoring existing network traffic without introducing additional load or latency. This non-intrusive approach minimizes risks, making it particularly suitable for sensitive OT environments. By analyzing network traffic, passive discovery provides essential details about devices and their interactions, helping organizations map relationships and dependencies across their networks.
However, passive discovery has inherent limitations. Many industrial devices, such as programmable logic controllers (PLCs) interacting with I/O devices, communicate exclusively within local subnets. These communications often remain confined to a single switch and do not pass through perimeter firewalls, making them difficult to detect through conventional methods.
Palo Alto Networks Industrial OT Security overcomes these challenges with advanced techniques such as port mirroring, TAP configurations, and ERSPAN. These methods significantly enhance visibility by capturing local communications that would otherwise remain hidden. While many solutions require standalone, dedicated sensors for passive discovery, which involve additional hardware deployments and increase costs and complexity, Palo Alto Networks leverages existing security infrastructure such as Next-Generation Firewalls (NGFWs) to perform passive discovery without the need for separate sensors. This approach simplifies deployment while enabling organizations to monitor mirrored or spanned traffic using flexible interface configurations, effectively detecting previously inaccessible communications, closing critical security gaps, and strengthening OT defenses.
Active discovery, or polling, complements passive methods by directly gathering detailed asset information from devices. It uses industrial protocols to request data without disrupting regular operations. This approach is particularly valuable for uncovering asset details such as firmware versions or serial numbers that often only become visible during specific interactions like programming or control connections. Active discovery is also essential in environments where switches do not support ERSPAN, RSPAN, or SPAN, or where configuring a TAP is not feasible. This may occur when switches lack available ports or simply do not support SPAN, a common limitation in industrial switches. By addressing these challenges, active discovery ensures a more complete and accurate view of assets across the network.
Palo Alto Networks’ PAN-OS network discovery plugin, starting with version 2.0.0, enables active discovery directly from its NGFWs. This eliminates the need for additional hardware and allows organizations to combine passive and active discovery within a single platform. The plugin provides complete control over discovery settings, including timing, protocols, ports, and target network segments, ensuring alignment with operational requirements. Active discovery is currently supported on PAN-OS 11.1.0, with plans to extend support to PAN-OS 10.2.14 in January 2025.
In cases where NGFWs lack network reachability to certain endpoints or run PAN-OS versions without polling support, the XSOAR engine offers an alternative solution. XSOAR facilitates active discovery across the network and integrates with other tools, consolidating asset information into a centralized platform.
XSOAR is particularly beneficial in the following situations:
Active discovery provides significant advantages by quickly collecting asset information that passive methods might miss. It is particularly effective for identifying devices that communicate infrequently or whose traffic is difficult to observe with traditional monitoring techniques. By integrating active and passive discovery, Palo Alto Networks delivers a comprehensive solution that ensures complete visibility and robust asset management in OT environments.
Parsing device configuration and inventory files is another effective method for gathering asset information. With Palo Alto Networks Industrial OT Security, users can upload device files directly into the platform. The system processes these files to extract valuable details, including IP addresses, serial numbers, firmware versions, hardware models, slot modules, and downstream devices.
This approach is particularly useful for identifying assets that do not actively communicate on the network or are inaccessible to other discovery methods, such as isolated network segments. However, the accuracy of this method depends on the timeliness of the uploaded files. If device attributes change and updated device files are not provided, the data may quickly become outdated. For this reason, configuration file parsing is most effective when used alongside passive and active discovery, ensuring a complete and accurate asset inventory.
Integrating with existing systems that store asset information is a powerful way to streamline the management of industrial assets. These integrations enable organizations to pull data from a variety of OT and IT solutions, ensuring accurate, up-to-date inventories while reducing manual effort.
For instance, Rockwell Automation’s Asset Center offers centralized versioning and tracking for automation assets, while CMDBs like ServiceNow provide a comprehensive framework for managing asset details across the enterprise. Additional integration options include network management tools such as Cisco Meraki, IP address management (IPAM) solutions like Infoblox and BlueCat, and network access control systems like Cisco ISE and Aruba ClearPass. Connecting these platforms with Palo Alto Networks Industrial OT Security allows organizations to automatically update asset information without requiring manual intervention.
These integrations facilitate seamless data sharing, enabling organizations to consolidate asset details from multiple sources into a unified platform. This approach ensures data consistency across operational and IT environments, making it easier to manage cyber risks within complex industrial systems efficiently. For more details on supported integrations, see the Palo Alto Networks Integration Guide.
Palo Alto Networks Industrial OT Security brings together passive and active discovery, configuration file parsing, and system integrations into a single, unified solution for comprehensive asset visibility and management. By leveraging our NGFWs and the PAN-OS network discovery plugin, organizations can enhance their asset inventories without the need for additional hardware. Advanced features such as VLAN insertion, TAP configurations, and ERSPAN ensure that all communications are effectively captured, addressing the inherent limitations of passive monitoring.
Visibility is critical, but that’s just the first step in securing industrial environments. With Palo Alto’s integrated approach, organizations gain not only asset visibility but also the ability to identify vulnerabilities, risk-prone behaviors, and interdependencies. These insights drive actionable strategies to reduce risk, including recommendations for network segmentation policies to isolate threats, virtual patching for systems that cannot be updated, and guidance on optimizing device configurations to strengthen security. By aligning these capabilities with operational requirements, organizations can confidently protect their environments while maintaining efficiency and uptime.
Take the next step in strengthening your OT security strategy with Palo Alto Networks. Explore the Palo Alto OT Security solution and deployment guides to see how our approach can transform your operations and enhance your security posture today.
