Securing Remote Access To Ot Environment

# Securing Remote Access to OT Environment

## When to Use

- When implementing or upgrading remote access architecture for OT environments
- When onboarding vendors who require remote access to OT systems for support and maintenance
- When implementing CIP-005-7 R2 requirements for remote access management including MFA
- When replacing legacy direct VPN access to OT networks with a secure jump server architecture
- When responding to an incident involving unauthorized remote access to industrial control systems

**Do not use** for securing IT-only remote access without OT components, for configuring VPN for corporate workers (see general VPN guides), or for physical access control to OT facilities.

## Prerequisites

- DMZ infrastructure (Level 3.5) between corporate IT and OT networks
- Jump server/bastion host platform (CyberArk, BeyondTrust, or hardened Windows/Linux server)
- Multi-factor authentication solution (Duo, RSA SecurID, YubiKey, smart cards)
- Session recording capability for audit trail compliance
- Firewall rules permitting remote access only through the DMZ intermediate system

## Workflow

### Step 1: Design Secure Remote Access Architecture

Implement a defense-in-depth remote access architecture with an intermediate system in the DMZ that prevents any direct network connectivity between external users and OT systems.

```yaml
# OT Remote Access Architecture
# Key principle: NO direct connection from external networks to OT systems

architecture:
  external_access_point:
    location: "Internet-facing firewall"
    service: "VPN gateway (IKEv2/IPsec or SSL VPN)"
    authentication: "Certificate + MFA (CIP-005-7 R2.4)"
    controls:
      - "Source IP allowlisting for vendor access"
      - "Time-based access windows"
      - "Bandwidth rate limiting"

  dmz_intermediate_system:
    location: "Level 3.5 DMZ"
    platform: "CyberArk Privileged Access Security or hardened jump server"
    function: "Session broker - terminates external connection, initiates new internal connection"
    controls:
      - "All sessions terminate at jump server (no pass-through)"
      - "Session recording with keystroke logging"
      - "Clipboard and file transfer restrictions"
      - "Session timeout after 30 minutes inactivity"
      - "Concurrent session limits per user"