Industrial Plants Must Move Beyond VPNs for Remote Access, Experts Advise

Virtual Private Networks (VPNs) remain the most widely used gateway for external parties to connect to industrial control environments, but cybersecurity specialists warn that the convenience they provide has turned them into the single most vulnerable entry point for many plants.

Manufacturing sites, energy facilities, and other critical infrastructure operators routinely grant network access to original equipment manufacturers, system integrators and remote engineers. A VPN tunnel offers a quick way to bridge the gap between corporate IT and the operational technology (OT) domain, allowing vendors to troubleshoot, update firmware, or provide on‑site support without physical presence.

That very ease, however, creates a lucrative attack surface. Compromised credentials, unpatched VPN software, and misconfigured access rules have enabled threat actors to infiltrate OT networks, move laterally, and manipulate processes. Recent breach investigations have repeatedly traced the initial foothold back to a VPN account that was either weakly protected or left active after a project ended.

Security professionals are urging organizations to replace traditional VPNs with more granular, identity‑centric solutions. Zero‑Trust Network Access (ZTNA) platforms, industrial remote‑access gateways that enforce strict segmentation, and purpose‑built OT firewalls can limit exposure by granting only the exact permissions required for a specific task and revoking them automatically after use.

The shift is already reflected in emerging vendor offerings and updates to standards such as IEC 62443, which now emphasize multi‑factor authentication, just‑in‑time provisioning, and continuous monitoring of remote sessions. Companies that adopt these controls can better align with regulatory expectations and reduce the likelihood that a remote‑access credential becomes a backdoor.

Looking ahead, analysts predict that plant operators will conduct comprehensive reviews of their remote‑access policies, integrating threat‑intelligence feeds and automated anomaly detection to spot suspicious activity in real time. As the industrial sector continues to digitize, the pressure to move away from legacy VPNs and toward a layered, zero‑trust approach is likely to intensify, making the transition a critical component of any robust cyber‑resilience strategy.