Secure Remote Access for OT
Remote access is no longer optional in modern industrial environments. Vendors, system integrators, OEMs, and internal engineering teams increasingly need the ability to connect to OT systems from outside the plant to troubleshoot issues, perform maintenance, or support distributed operations. What has changed is the level of risk associated with doing this incorrectly.
In OT environments, remote access is not just a cybersecurity concern. Poorly controlled access can affect plant safety, system availability, and regulatory compliance. In many environments, remote access grows out of convenience rather than design. A VPN is left running, credentials are shared between teams, and file transfers happen without clear oversight. Over time, this creates access paths that were never intentionally planned.
Arista Cyber approaches remote access as an operational control problem, not just a connectivity issue. We help organisations introduce controlled access to OT systems in a way that supports daily work without weakening plant stability.
Instead of extending the OT network outward, a Zero Trust approach keeps access tightly scoped. Each session is treated as temporary, observable, and limited in reach, so remote activity can take place without eroding the integrity of industrial systems.
CONTROLLED, CENTRALIZED, AND COMPLIANT REMOTE ACCESS FOR RESILIENT OPERATIONS
Why Secure Remote Access Matters in OT
Remote access solutions designed for IT environments often fail when applied directly to OT. Industrial systems were not built to tolerate constant external connectivity or broad access privileges. Legacy controllers, safety systems, and production equipment require a more cautious approach.
In many incidents, the problem is not that remote access exists, but that it persists. Accounts are left active long after work is complete. Access paths are reused for convenience. Monitoring is limited, making it difficult to know who connected, when, and what they did.
A secure remote access strategy for OT must therefore focus on control, visibility, and intent. Access should exist only when needed, be restricted to specific systems, and be fully observable by operations and security teams.
Key Advantages
Secure remote access should enable productivity without weakening the environment it connects to. A structured, centralised approach provides that balance.
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1.Protect OT networks while enabling remote operations
Access is granted only to approved users and limited to the systems and functions required for the task at hand. This reduces unnecessary exposure across the OT network. -
2.Centralised monitoring and control
All remote connections are managed from a single control point. This makes it easier to see who is connected at any given time, why access was granted, and when it should end. Connections are no longer left open by default. -
3.Time-based access
Access can also be limited to specific time windows, so once work is complete, the pathway closes automatically rather than lingering in the background. -
4.Controlled file transfer
File movement into and out of the OT environment is governed and monitored, reducing the risk of unauthorised changes or malware introduction. -
5.Standards and policy alignment
Remote access controls are designed to support IEC 62443 requirements and align with internal security policies and operational procedures.
When remote access is tightly controlled and centrally managed, it becomes far easier to support operations without increasing risk.
Deliverables
1.Secure remote access architecture design.
A ZTNA-based remote access architecture designed around how your OT environment actually operates, taking into account risk, access needs, and operational constraints.
2.Access control and authentication policies
Clear rules that define who is allowed to connect, which systems they can reach, and under what circumstances access should be granted.
3.Implementation guidance and monitoring setup
Practical guidance for deploying the solution and setting up monitoring so access can be reviewed and managed centrally.
These deliverables are structured to support both technical execution and long-term governance.
Our Approach
We start by looking at how the organization’s current remote access is being used. Who connects, why they need access, and which tools are in place is thoroughly investigated. This often reveals informal workarounds or long-standing access paths that no one actively manages anymore.
From that point, a segmented remote access model is designed using Zero Trust principles. Access is issued per user and per session, so privileges exist only for as long as they are needed.
Authentication is strengthened through multi-factor checks, reducing dependence on passwords alone. Where appropriate, integration with Windows Active Directory keeps identity management centralised and familiar for internal teams.
Remote access activity is logged and integrated with your SIEM platform. This provides visibility into access events, session behaviour, and anomalies, supporting both incident response and compliance reporting.
Clear documentation and guidance are provided so teams understand how access should be used and what to expect during normal operations.
Designed for Operational Reality
Secure remote access must work within the constraints of industrial operations. Solutions that interrupt production, require frequent manual intervention, or rely on complex workflows are unlikely to be adopted consistently.
Our designs prioritise:
- 1. Minimal operational disruption
- 2. Clear ownership and accountability
- 3. Ease of monitoring and review
- 4. Compatibility with legacy OT systems
The aim is to support existing workflows, not force teams to bend around tools that were designed for IT environments.
Compliance Without Friction
Remote access is a frequent focus during OT security audits. Unclear access paths, shared credentials, and a lack of logging often raise concerns.
Because access controls and monitoring align with IEC 62443, evidence is available when auditors ask for it, without scrambling to reconstruct how access was managed.
Ready to Secure Remote Access to Your OT Environment?
Remote access does not have to be a trade-off between convenience and safety. With the right architecture, it is possible to support remote operations while maintaining strong control over critical systems.
If your organisation relies on remote connectivity into OT environments, now is the right time to review how that access is granted, monitored, and governed.
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