Network Port Security & RJ45 Hardening
Requirement: This module addresses IACS UR E26 (Section 5), mandate for protecting network infrastructure from unauthorized physical access and the “tamper-evident” requirements for OT cabinets.
While digital firewalls guard the perimeter, the internal OT network is often “flat” and trusting. An unused RJ45 port on a bulkhead or an open switch port in an Engine Control Room (ECR) is an open invitation for lateral movement and packet sniffing.
The Reality: Vulnerable Entry Points
On a vessel, the physical environment is as much of a threat as the digital one. Unlike a corporate office, maritime OT environments often have network jacks located in accessible areas like the Bridge, Cargo Control Room, or even public corridors. These ports are frequently forgotten until a security incident occurs. The risk is not just about a hacker sitting down with a laptop; it is about the “innocent” connection of unauthorized devices that can introduce broadcast storms or bridging loops that shut down vessel communications entirely.
The “Shadow” Connection
Crew members or contractors often plug personal laptops or “travel” Wi-Fi routers into spare OT ports to get internet access. This creates an unmonitored bridge between the secured OT backbone and the outside world.
Transient Tool Risks
External technicians often use portable diagnostic tools that require a network connection. Without port hardening, these “transient” devices can bypass all level-3 security controls simply by being physically plugged in.
The Solution: Multi-Layered Port Hardening
The goal is to ensure that a physical connection does not automatically grant network access.
Switch Hardening: MAC Sticky Script
Prevent unauthorized device swapping by “locking” the port to a specific MAC address (Cisco/Hirschmann):
# Access the interface
interface gigabitEthernet 0/1
# Enable port security
switchport port-security
# Lock to the first MAC address detected
switchport port-security mac-address sticky
# Shutdown port if a different device is connected
switchport port-security violation shutdown
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OS Hardening & Service Disabling
OS Hardening & Service Disabling Regulatory Context: IACS UR E27 (Section 4.3.1) mandates the hardening of all OT hosts....
