Full Report
Do security issues associated with working remotely affect critical infrastructure enterprises? Should organizations take additional protective measures? A view of regulators in the area of information security.
Analysis Summary
# Best Practices: Secure Remote Access for Critical Infrastructure (CI)
## Overview
These practices address the unique security challenges of extending remote access to Critical Infrastructure (CI) and Industrial Control Systems (ICS). They aim to mitigate risks such as unauthorized access to operational technology (OT), malware infiltration via remote endpoints, and the compromise of sensitive data in distributed environments.
## Key Recommendations
### Immediate Actions
1. **Inventory Remote Access Points:** Identify all existing VPNs, RDP instances, and third-party remote maintenance ports. Close any unauthorized or "shadow" access points.
2. **Enforce Multi-Factor Authentication (MFA):** Mandate MFA for all remote connections, specifically focusing on hardware tokens or push-based mobile apps rather than SMS.
3. **Endpoint Health Checks:** Implement "pre-flight" checks to ensure any device connecting (BYOD or Corporate) has active antivirus and the latest security patches.
4. **Disable Redundant Services:** Turn off RDP on internet-facing servers and use a gateway or VPN tunnel instead.
### Short-term Improvements (1-3 months)
1. **Network Segmentation:** Isolate the OT/ICS environment from the corporate IT network using a Demilitarized Zone (DMZ) and jump hosts.
2. **Principle of Least Privilege (PoLP):** Review and restrict user permissions so that remote workers can only access the specific subsets of the network required for their role.
3. **Log Centralization:** Direct all remote access logs to a centralized Security Information and Event Management (SIEM) system for real-time monitoring.
4. **Formalize VPN Policies:** Use split tunneling only when necessary; prioritize full tunneling for high-security OT environments to ensure all traffic is inspected.
### Long-term Strategy (3+ months)
1. **Zero Trust Architecture (ZTA):** Transition from perimeter-based security to a Zero Trust model where "never trust, always verify" applies to every connection request.
2. **Privileged Access Management (PAM):** Deploy a PAM solution to manage and record sessions for technicians and third-party vendors accessing critical systems.
3. **Continuous Security Awareness:** Implement specialized training for OT operators on the specific threats related to remote manipulation of physical processes.
## Implementation Guidance
### For Small Organizations
- **Cloud-Based Security:** Leverage built-in security features of reputable cloud providers (e.g., Azure AD) for identity management to save on infrastructure costs.
- **Managed Service Providers (MSPs):** Partner with an MSSP that has specific experience in ICS/OT security to monitor logs.
### For Medium Organizations
- **Hardware VPN Gateways:** Move away from software-only VPNs to dedicated hardware appliances capable of deep packet inspection (DPI).
- **Vulnerability Management:** Establish a monthly cadence for scanning remote-access infrastructure for vulnerabilities.
### For Large Enterprises
- **Redundant Jump Hosts:** Deploy tiered jump server architectures where users must pass through an IT-layer jump host before reaching an OT-layer jump host.
- **24/7 SOC Integration:** Integrate remote access telemetry into a 24/7 Security Operations Center (SOC) with automated incident response playbooks.
## Configuration Examples
* **VPN Configuration:** Set session timeouts to a maximum of 8 hours to prevent "zombie" sessions.
* **Firewall Rules:** Implement "Deny All" as the default rule, only explicitly allowing required ports for RDP/SSH via the VPN tunnel.
* **RDP Hardening:** Change default RDP port 3389 to a non-standard port (though this is "security by obscurity," it reduces automated bot scanning) and enable Network Level Authentication (NLA).
## Compliance Alignment
- **NIST SP 800-46:** Guide to Enterprise Telework, Remote Access, and BYOD Security.
- **ISO/IEC 27001:** Information security management systems.
- **IEC 62443:** Security for industrial automation and control systems.
- **CIS Controls:** Specifically Control 12 (Network Infrastructure Management) and Control 4 (Secure Configuration of Enterprise Assets).
## Common Pitfalls to Avoid
- **Mixing IT and OT Access:** Using the same VPN gateway for office staff and engineers controlling physical machinery.
- **Ignoring Third-Party Vendors:** Allowing contractors permanent, unmonitored "backdoor" access for maintenance.
- **BYOD Without Control:** Allowing personal devices to connect to critical segments without MDM (Mobile Device Management) or strict isolation.
## Resources
- **Kaspersky ICS CERT:** hxxps[:]//ics-cert[.]kaspersky[.]com/
- **CISA (Cybersecurity & Infrastructure Security Agency):** hxxps[:]//www[.]cisa[.]gov/topics/critical-infrastructure-sectors
- **NIST Cybersecurity Framework:** hxxps[:]//www[.]nist[.]gov/cyberframework