Complete Guide to VPN Replacement for OT/ICS
Virtual Private Networks (VPNs) have long been used for remote access. In OT and ICS environments, that default is increasingly misaligned with how industrial access actually works, including third parties, unmanaged devices, and environments that cannot tolerate disruption.
VPNs increase risk by extending internal network access to remote users, relying on endpoint trust, and offering limited visibility into what happens after connection. This guide explains why VPNs fall short in OT and ICS, the compliance and operational drivers pushing change, and what modern alternatives look like.
VPN replacement in OT and ICS means moving from network tunnels to session-based remote access that is identity-enforced, time-bound, and protocol-isolated so users can complete work without exposing the control network.
Key Takeaways
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VPNs were designed for enterprise IT use cases and introduce serious risk when applied to OT and ICS environments.
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OT remote access now requires identity-based, session-specific controls that isolate access without exposing the network.
Not sure what a VPN is? You can read the full glossary definition in “Virtual Private Networking (VPN).”
Why are VPNs considered insecure in OT environments?
VPNs provide network tunnels between remote users and internal systems. In OT and ICS, that model creates risk because control environments include sensitive systems, legacy infrastructure, and devices not designed for broad connectivity.
The core issue is network extension. Once connected, VPN users often gain access to more of the environment than intended. In OT, that can include PLCs, HMIs, and SCADA servers that influence real-world processes and safety functions.
VPNs also depend on endpoint trust. If a contractor laptop or technician device is compromised, the VPN path can be used for lateral movement, disruption, or data access. Many VPN deployments also lack session-level controls and visibility, which makes it hard to detect misuse or contain an incident during access.
VPNs often do not support the access governance OT environments require. Static credentials, shared accounts, and flat permissions reduce traceability and make it harder to demonstrate least privilege, time-based access, and revocation.
Key Takeaways
- VPNs extend network access in a way that increases exposure to critical OT systems.
- VPNs rely on endpoint trust and lack the session-level control and visibility expected in OT remote access.
What is the attack surface created by VPNs and jump servers?
VPNs and jump servers increase the OT attack surface by creating pathways from external users into internal systems without consistent session-level isolation and oversight.
With VPNs, a remote device effectively becomes part of the internal network. If that device is compromised through malware, credential theft, or remote access tooling, it can be used to reach OT assets. This risk is amplified when users connect from unmanaged endpoints and third-party devices.
Jump servers are commonly used to limit where VPN users can go, but they often introduce their own issues. They create a concentrator for remote access, can become a single point of failure, and are frequently complex to maintain. They still depend on credentials, remote desktop workflows, and configuration discipline. Misconfiguration or weak controls can undermine the intended segmentation benefits.
Instead of routing users through a jump server, a session-brokering model mediates RDP, SSH, VNC, and web sessions through a controlled interface without making the user device part of the OT network.
Both VPNs and jump servers often lack strong visibility. Organizations may not get session recording, per-user attribution, or real-time oversight by default, which affects detection, investigation, and compliance evidence.
Read more about jump servers in this full glossary definition “Jump Server / Jump Box.”
How Xona Addresses This
Xona replaces network-level access with protocol-isolated, session-based connectivity. Users access OT systems through a browser interface without forming a direct network connection. This removes VPN tunnels and reduces dependence on endpoint trust, while improving session oversight and auditability.
Key Takeaways
- VPNs and jump servers expand attack surface by enabling network-layer access with limited session-level isolation and oversight.
- These paths increase exposure to credential compromise, lateral movement, and operational disruption.
What are the compliance drivers for VPN replacement in OT?
Critical infrastructure standards increasingly require stronger remote access governance than traditional VPNs typically provide. Frameworks such as NERC CIP, IEC 62443, TSA SD02E, Saudi NCA OTCC-1:2022, and NIS2 expect controls such as identity enforcement, access segmentation, session monitoring, and traceability.
VPNs can fall short because network access can be broad after connection, and activity is not always attributable at a session level. Jump servers used alongside VPNs may also lack protocol isolation, session recording, and role-based workflows tied to time-bound access.
Modern compliance expectations commonly include multi-factor authentication, identity-based access, time-based access, session logging, and centralized governance. Auditability now depends on being able to show who accessed what, when, and under what constraints.
Read more about compliance requirements in this full glossary definition “Remote Access Compliance.”
How Xona addresses this
Xona enforces identity-based access with role and time constraints and records sessions for audit needs. Sessions are authenticated, logged, and can be recorded with metadata and optional video playback. Access is controlled through policy without exposing credentials or extending the network layer.
Key Takeaways
- VPNs and jump servers often lack the visibility and granularity required to demonstrate least privilege and traceability in OT.
- Compliance frameworks increasingly expect identity enforcement, time-limited access, and monitored sessions.
What are the alternatives to VPNs for secure OT remote access?
VPN replacement in OT requires a shift from network-based access to identity-based, session-specific access that isolates users from the underlying infrastructure. This aligns with Zero Trust principles and addresses common limitations of VPNs, jump servers, and credential-centric access models.
PAM is an adjacent category focused on privileged credential governance, while VPN replacement emphasizes replacing network-layer connectivity with session-layer access control and oversight.
Modern alternatives commonly use protocol isolation so a user does not form a direct network connection to OT systems. Sessions are brokered through an access gateway that mediates protocols such as RDP, SSH, VNC, and web access through a controlled interface.
Common supporting capabilities include:
- Credential vaulting and injection to avoid exposing or sharing OT credentials
- Time-based access to scope access to approved windows
- Real-time session supervision, including monitoring and termination
These models can reduce operational friction by being agentless and avoiding client installation on user devices or OT assets.
Not sure what PAM tools are? Read all about them in this full glossary definition “Privileged Access Management (PAM).”
How Xona addresses this
Xona provides browser-based OT access using protocol isolation and session brokering. It enforces identity- and time-based access policies and removes the need for VPN tunnels, jump servers, and credential distribution.
Key Takeaways
- OT VPN replacement is centered on session control, protocol isolation, and identity-based access.
- Modern alternatives can reduce exposure while improving governance and usability.
How does VPN replacement reduce cost and complexity?
VPN and jump server deployments often create operational overhead beyond licensing. Teams may manage clients, appliances, firewall rules, credentials, and troubleshooting across distributed sites and user groups.
Onboarding new vendors or technicians can involve repeated manual work, including credential provisioning and access troubleshooting. In OT, these delays can affect time-sensitive maintenance and incident response.
VPN replacement can also reduce breach and audit response costs when sessions are attributable, logged, and reviewable.
How Xona addresses this
Xona reduces operational complexity by eliminating VPN clients and jump hosts and simplifying access workflows through policy-governed browser sessions. This can reduce onboarding friction, support burden, and effort associated with audit evidence and investigations.
Key Takeaways
- VPN replacement can reduce support overhead, manual provisioning work, and the operational impact of access troubleshooting.
- Session-level visibility and attribution improve incident investigation and audit response.
What does a modern OT access architecture look like without VPNs?
Modern OT access architectures avoid extending the network to the user. Instead, access is brokered at the session layer through a hardened gateway that mediates the connection without exposing the internal network.
Users access OT systems through browser-based workflows where sessions are protocol-isolated and time-bound. Access is policy-driven and identity-enforced, with real-time visibility into sessions.
Credential injection reduces reliance on static account provisioning. Session logging and optional recording support traceability and auditability.
Modern OT access can integrate with:
- Identity providers (IdPs) for authentication
- SIEMs for centralized event logging
- Ticketing systems for access workflow governance
How Xona addresses this
Xona supports session brokering, protocol isolation, and identity enforcement through a browser-based access model without VPN tunnels or endpoint agents. Access is governed by policy and can integrate with enterprise identity and security systems.
Key Takeaways
- Modern OT access replaces VPN tunnels with protocol-isolated, session-based access that avoids network exposure.
- Identity integration and session observability support secure, compliant remote operations.
Summary: VPNs served their time. OT needs a different model.
VPNs were not designed for modern OT environments. They extend network access, depend on endpoint integrity, and often lack the session-level governance and visibility needed for high-stakes remote operations.
VPN replacement is an architectural shift toward session-specific, identity-enforced workflows that isolate users from sensitive systems. This approach can reduce exposure, improve auditability, and simplify remote access operations across internal and third-party use cases.
Key Takeaways
- VPN replacement enables secure, auditable access without extending the network or relying on endpoint trust.
- OT access models should prioritize session isolation, identity enforcement, and traceability.
Frequently Asked Questions
Why are VPNs not aligned with Zero Trust in OT?
VPNs create a trusted network path after connection, which undermines least privilege and session isolation. In OT, that can expose more of the environment than intended.
Can VPNs be used safely in regulated OT environments?
VPNs can be hardened, but they often do not natively provide fine-grained access control, per-user traceability, session recording, and protocol segmentation expected by many OT frameworks.
What is protocol isolation and why does it matter?
Protocol isolation prevents a user device from forming a direct network connection to an OT system. The access platform mediates protocols such as RDP, SSH, VNC, or web access and enables session-level control, logging, and auditability.
How does VPN replacement help with compliance audits?
VPN replacement can support controls such as multi-factor authentication, time-based access, and session logging, enabling clearer evidence of who accessed what, when, and under what constraints.
What are the key differences between VPNs and Secure Remote Access platforms?
VPNs extend the internal network and rely on endpoint trust and broad permissions. Secure remote access platforms emphasize session-level control, protocol isolation, identity-based access, and browser-based workflows to reduce network exposure and improve governance.
