OT Control Tower - Zero Trust for Industrial Environments

OT identity has become a critical pillar of industrial cybersecurity. As traditional air gaps and perimeter defenses erode with IT/OT convergence, implicit trust models are no longer viable. Attackers increasingly exploit identity weaknesses—such as shared credentials or unsecured access—to compromise OT environments.

Zero Trust shifts this paradigm by requiring continuous verification of every user, device, and access request. This is especially urgent in OT, where breaches can disrupt production, impact safety, and affect critical services.

Rising threat levels, combined with regulatory pressure from frameworks like NIS2, NIST CSF, and ISA/IEC 62443, are driving organizations to modernize identity governance. Adopting unified identity and Zero Trust models is now essential to reduce risk and ensure compliance.

Many organizations struggle with fragmented and outdated OT identity practices that undermine security:

• Legacy Shared Accounts: It’s common to find generic logins (e.g. “Operator”) and default passwords still in use on HMIs, PLCs, or engineering workstations. Shared credentials mean no individual accountability and easy targets for attackers.
• Siloed Systems & Vendor Access: A typical plant has numerous control systems, each with its own user directory. Third-party contractors often connect via VPNs or modems with separate credentials. There’s no single view of who has access across these silos, creating blind spots.
• Lack of Visibility & Governance: Because identities aren’t centrally managed, security teams can’t easily answer “Who can access system X?” or “When was this account last used?”. User access reviews and audits become manual, time-consuming chores – if they happen at all.
• Compliance Pressure: Frameworks like NIST CSF and ISA/IEC 62443 explicitly call for unique user IDs, role-based access, multi-factor authentication (MFA), and audit trails in OT. Without better tools, companies find it difficult to prove compliance with these requirements, risking audit findings or regulatory penalties.

These challenges collectively increase the risk of unauthorized access and hinder both security operations and regulatory compliance. They set the stage for why a new approach is needed.

A unified OT identity layer means having one coordinated system to manage all identities and access rights across the OT environment. Instead of disparate accounts on each device or application, companies integrate OT assets with a central identity governance platform (e.g. extending their enterprise IAM solution). This unified layer is foundational because it solves the “you can’t secure what you can’t see” problem. Key benefits include:

• Complete Visibility: Every user (employees, contractors, vendors) and even service accounts in OT are inventoried in one place. You always know who has access to what systems. This is akin to maintaining an OT CMDB for identities.
• Consistent Access Controls: Policies such as unique user credentials, password complexity, and MFA for remote or elevated access can be enforced uniformly. No more unchecked shared passwords on critical equipment.
• Streamlined Workflows: Provisioning or revoking access becomes far more efficient. For example, when a new engineer joins, a single workflow can grant all required OT access based on role; when someone leaves, one action removes their privileges everywhere. This reduces errors and delays while ensuring least privilege and timely de-provisioning.
• Improved Governance: Regular access reviews and certifications can be done centrally. You can quickly audit who has access to a given system and produce logs of all changes. This greatly simplifies compliance with standards and provides evidence for audits.

In short, unifying OT identity transforms access management from a patchwork of local practices into a cohesive, security-driven program. It creates the foundation on which advanced security strategies like Zero Trust can be built in the OT domain.

Zero Trust is a security philosophy of “never trust, always verify” – even for insiders or trusted devices. Implementing Zero Trust in OT means adapting its well-known pillars (Identity, Device, Network, Application, Data) to industrial realities. Below is a simplified view of how key Zero Trust principles map to OT:

Practical challenges: Applying Zero Trust in OT must account for legacy constraints. Some devices can’t support modern authentication or encryption – so compensating controls (like network enforcement points or jump boxes) are used to impose identity verification. Safety and uptime requirements mean changes must be introduced carefully. Solutions include techniques like just-in-time access (granting privileges only for a limited duration/task) and “monitor first” approaches (observing traffic for threats without immediately blocking critical processes). Despite these challenges, companies are finding ways to progressively implement Zero Trust controls in OT networks – often starting with the highest-risk remote access pathways and then expanding inward. The end goal is an environment where every interaction is authenticated and authorized, drastically limiting an adversary’s ability to move or cause damage if they do get in.

ServiceNow’s Operational Technology Management (OTM) platform provides the operational visibility, governance framework, and process foundation needed to support OT Identity and Access Management (OT IAM) and Zero Trust initiatives across industrial environments. Built on the familiar ServiceNow platform, OTM helps organizations establish a trusted inventory of OT assets, define ownership and accountability, automate operational workflows, and maintain contextual information critical for access governance and security decision-making. By connecting people, processes, and OT assets within a unified platform, OTM enables organizations to strengthen identity-centric security controls and accelerate the adoption of Zero Trust principles. Key supporting capabilities include:

• Identity Lifecycle Integration: OTM ties into HR and IAM systems so that when personnel join, change roles, or leave, their OT access is auto-provisioned or revoked accordingly. A new technician, for example, can be granted all appropriate OT system accounts via one onboarding request (with proper approvals) instead of creating accounts ad hoc on each system.
• Role-Based Access & Workflows: With OTM, organizations define OT-specific roles (like Plant Operator, Control Engineer, Vendor Technician) with predefined access rights. Any access request or change (e.g., a contractor needing access to a particular HMI) goes through a ServiceNow workflow for approval, ensuring accountability and traceability. No access is granted without the proper electronic paper trail.
• Integration with OT Asset Inventory (CMDB): OT CMDB knows all your devices and systems. This context allows for smart access decisions – e.g., only users with certain training can request access to a safety system, or if a device is flagged with a critical vulnerability, additional authorization might be required for access. Linking identities to assets also means you can see, for instance, all users with permissions on a given PLC model or production line.
• Unified Logging & Audit: Every OT access request, approval, and provisioning action is logged in one place. This unified log is a goldmine for auditors and incident responders. If a security incident occurs, you can quickly pinpoint which accounts were active on the affected system and when. For compliance, generating reports on OT access (who accessed what, when, with manager approvals) is straightforward, helping demonstrate adherence to standards like IEC 62443 and internal policies.
• Bridging IT and OT Teams: Because OTM resides in the same platform as IT service management and security operations, it fosters collaboration. IT security staff and OT engineers share a common interface and data. For example, an IT SOC analyst investigating an alert can pull up OT context (asset details, recent access changes) in ServiceNow. This breaks down silos between IT and OT security processes, resulting in faster, more coordinated threat response and streamlined operations.

Overall, ServiceNow OTM provides the operational foundation that enables organizations to implement and scale OT identity and access management capabilities while supporting the adoption of Zero Trust principles such as least privilege, role-based access, and continuous verification. By centralizing OT asset information, ownership, lifecycle data, and operational workflows, OTM helps create the visibility, governance, and process controls required to manage access effectively across industrial environments. This enables organizations to extend modern identity governance practices into manufacturing and critical infrastructure operations while reducing administrative effort and improving operational resilience.

Unified OT identity and Zero Trust add value in many real-world scenarios. A few high-impact use cases:

• Secure Vendor Remote Maintenance: Rather than sharing a VPN password or always-on connection, plants can use OT IAM to give vendors time-limited, scoped access to specific equipment. For example, a contractor gets a unique account that only works for Plant A’s boiler control system during this week’s maintenance window, with MFA required. All activity is tracked. This reduces third-party risk dramatically.
• Operator and Engineer Access Control: Day-to-day staff access can be finely managed. An operator logging into a control station uses their personal credentials (no more generic logins), and if they need elevated permissions to change a critical setting, a supervisor’s electronic approval may be required via workflow. This ensures safety-critical actions are authenticated and approved, without hampering responsiveness.
• Onboarding/Offboarding Automation: When a new engineer is hired or a contractor comes on board, a unified identity approach means they can be granted all appropriate OT system permissions in one process (e.g., giving them access to the SCADA system and maintenance scheduler relevant to their role). Similarly, when someone leaves, one action in OT IAM revokes all their OT accesses. This prevents “leftover” accounts that often go unnoticed on plant systems.
• Incident Response & Audit: Suppose a potential breach is detected on a PLC. With unified identity management, the security team can immediately identify which user account was associated with the anomalous activity and lock it down across all systems. Later, for audit, the team can show exactly who had access to that PLC and that proper approvals were in place. These capabilities turn what used to be multi-day investigations into quick, precise actions, limiting damage and improving oversight.

By addressing OT identity holistically and adopting Zero Trust, organizations can expect significant benefits:

• Improved Resilience: Strong identity controls reduce the risk of incidents that cause downtime. And if an incident occurs, it’s contained faster. This means greater uptime and safety, directly protecting revenue and lives.
• Reduced Risk Exposure: Eliminating common vulnerabilities like shared passwords and securing remote access closes off major attack vectors. The overall cyber risk in OT drops, which also lowers the chances of costly regulatory penalties or reputational damage from a breach.
• Enhanced Compliance & Governance: A unified OT identity layer makes it far easier to comply with standards and pass audits. Companies can confidently meet requirements from NIST CSF, IEC 62443, and other regulations by showing they have unique user accounts, MFA, and audit trails in place. This not only avoids penalties but can be a business enabler (e.g., satisfying due diligence for partners or insurance).
• Operational Efficiency: Automation of identity workflows saves time for IT, security, and operations teams. What used to take dozens of emails and manual updates (like provisioning an account on five different systems) can be done with one request. Fewer mistakes and faster access translate to more agile operations and less frustration for engineers who can get to work quicker. Over time, lower admin overhead and more robust security also bring cost savings (for example, less need for emergency incident spending or redundant legacy access tools).

In essence, unified OT identity + Zero Trust turns security from a potential headache into a business advantage – enabling digital transformation in factories and plants with confidence.

The convergence of IT and OT makes unified identity and Zero Trust essential for industrial security. As threats grow and regulations tighten, fragmented identities and implicit trust models are no longer viable. Identity is the new perimeter—and every access must be verified.

Adopting a unified OT identity layer with a Zero Trust approach delivers stronger security, improved compliance, and more efficient operations. Platforms like ServiceNow provide a practical foundation to integrate identity, asset, and access governance in industrial environments.

Now is the time to act: Whether you’re a CISO, OT leader, or plant manager, consider taking the next step: assess your current OT identity gaps, select solutions that can help orchestrate the end-to-end process, and pilot a Zero Trust approach in a critical area of your operations. The path to a unified OT identity and Zero Trust architecture will fortify your organization’s resilience and set you up for safer, smarter growth in the era of digital industrial operations.