Why Remote Access to Industrial Operations Is the Biggest Unmanaged Risk
Industrial operations have never been more connected – or more exposed. As plants modernize and depend on third-party vendors, integrators and remote experts, access practices haven’t kept pace with the threat landscape.
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The connectivity that drives uptime and efficiency has quietly become one of the largest unmanaged attack surfaces in operational technology. Adversaries – including nation-state actors – are actively probing these pathways. Recent CISA advisories have called out insecure remote access as a primary entry point into critical infrastructure.
It’s time to rethink remote access from the ground up – with zero trust network access purpose-built for OT.
We Solved This in IT. Why Is OT Still Struggling?
VPNs and jump servers offer an illusion of security: Traditional VPNs were designed for IT. Repurposed for OT, they grant broad network-level access – often placing a remote user on the same flat network as programmable logic controllers, human-machine interfaces and safety instrumented systems. Jump boxes are shared, rarely patched and poorly monitored. Neither enforces least-privilege, identity-aware or session-level access. The mental model is wrong: These tools answer “How do I get someone connected?” rather than “How do I ensure only the right person touches the right asset, only when needed, with full visibility?”
Operational urgency overrides security: When a critical system goes down, VPN-based access is too slow and has high friction. Teams adopt workarounds that become standard practice: shadow remote access tools proliferate, shared credentials circulate and temporary access becomes permanent.
Access hygiene is forgotten: Vendor accounts from a commissioning project two years ago still have active credentials. Firewall rules opened for emergency support remain open months later. Without centralized visibility and automated life cycle management, organizations accumulate security debt with every engagement.
You can’t protect what you can’t see. Many organizations can’t monitor or record what remote users do once connected. If a misconfiguration or unauthorized change occurs, there’s no audit trail – a compliance concern as much as a security one under NERC CIP, IEC 62443, NIS2 or sector-specific regulations.
Where the Risk Meets the Reality
Third-party vendor and OEM access: Third parties represent one of the most common – and least controlled – pathways into OT, often using their own tools, devices and shared accounts. A zero trust network access approach means identity verification before any connection, access scoped to the individual asset, time-bound sessions and full session recording.
Remote operations and engineering staff: The shift toward centralized remote operations accelerated during the pandemic and hasn’t reversed. Engineers need to reach specific controllers across multiple sites – but not historians or safety systems. ZTNA delivers continuous posture verification and granular role-based policies with centralized management.
Emergency and break-fix access: A critical process alarm fires at 2 a.m. Speed is paramount, and the temptation to bypass controls is enormous – yet this is precisely when an attacker might exploit the chaos. ZTNA provides pre-approved on-demand workflows, lightweight approval mechanisms, complete session capture and automatic access revocation when the window closes.
From IT Buzzword to OT Practice
Strip away the hype, and zero trust is a set of principles that directly address the most dangerous gaps in industrial remote access:
- Verify explicitly: Every user, device and session should be authenticated based on identity, role, the specific asset and real-time context. Network location alone is never a reason to trust.
- Least-privilege access: Scoped to a single asset and action – not a subnet, VLAN or entire production environment, with no standing privileges.
- Assume breach: Design every layer so a compromised credential cannot cascade. Segment ruthlessly. Log everything – because in OT, unchecked lateral movement means physical consequence, not just data loss.
ZTNA Built for OT
ZTNA built for OT doesn’t demand a forklift replacement. It means layering identity-centric, asset-level controls that coexist with legacy systems, proprietary protocols and the narrow change windows that define operational reality – aligned with NIST 800-207, IEC 62443, NIS2 and CISA’s secure remote access guidance.
Traditional VPN-based access grants a network pathway and relies on assumptions – assumptions that segmentation is in place, that credentials haven’t been shared and that the vendor disconnects when done. ZTNA replaces assumptions with enforcement: every session authenticated, every connection scoped to the specific asset and every privilege expired the moment work is complete. No persistent tunnels. No implicit trust. The attack surface doesn’t just shrink – for unauthorized users, it disappears.
Why the ZTNA Gateway Placement Matters
Most ZTNA solutions centralize the gateway in the industrial DMZ, placing it too far from the assets it protects. In environments where IP addresses are reused and assets sit behind NAT boundaries, a distant gateway can’t reach them – forcing organizations to expose private IPs and making lateral movement prevention nearly impossible.
Cisco Cyber Vision’s Secure Equipment Access solves this problem by embedding the ZTNA gateway directly into Cisco industrial switches and routers already deployed throughout the OT network. Secure Equipment Access activates the gateway as a software feature on existing equipment – putting enforcement in close proximity to every asset regardless of IP address or NAT configuration.
The result: Assets stay hidden from discovery, zero trust policies and microsegmentation are enforced at the network edge, and administrators retain granular control over who connects, when and to what – all managed through a cloud-based trust broker. Whether access is clientless, browser-based or agent-based for tasks like PLC programming, the core tenets hold: default deny, identity-based access, resource isolation and no lateral movement.
Critically, Secure Equipment Access also bridges the IT-OT divide: IT defines and enforces the underlying security policies, while OT teams can authorize remote access requests on their terms, for example at 2 a.m. on a weekend – ensuring both consistent security governance and operational flexibility across the operations.
Time to Act
The question is no longer whether to modernize OT remote access – it’s how quickly you can move from ad hoc practices to a principled ZTNA approach built for OT realities.
Ask yourself: How many active vendor accounts exist in your environment right now, and what do they have access to? How many remote access sessions are active? Can you produce a complete audit trail for every remote session in the last 90 days?
If those answers are uncomfortable, it’s time to act. Organizations that get this right won’t just be more secure – they’ll be more operationally resilient, more audit-ready and better positioned to scale industrial digital transformation with confidence.
See how Cisco Cyber Vision’s Secure Equipment Access – purpose-built ZTNA for OT – helps organizations tackle this challenge. For more information, click here.