Maritime 5G Security: High-Speed Communication Protection

Why 5G Is Arriving in Maritime Now

For most of the last two decades, vessel connectivity meant satellite. VSAT, Inmarsat FleetBroadband and Iridium gave a ship a narrow, expensive and often intermittent link to shore. That economic reality shaped the cyber threat model: systems on board were updated infrequently, remote access was rare, and the natural latency and cost of satcom acted as an accidental security control. An attacker on shore could not simply maintain a persistent interactive session into a bridge system over a link that dropped every few minutes and charged by the megabyte.

5G changes that calculation in two distinct contexts. The first is coastal and near-shore operation, where public 5G networks from terrestrial carriers now offer multi-hundred-megabit links to vessels operating within a reasonable distance of the coast. The second is the port and terminal environment, where private 5G networks are being deployed for crane automation, autonomous yard vehicles, container tracking sensors and remote equipment control. A modern container terminal increasingly runs on a private 5G backbone the way an older one ran on industrial WiFi and fixed fibre.

Layered on top of both is the rise of low-earth-orbit satellite broadband, which behaves much more like a terrestrial link than legacy geostationary satcom. The combined effect is that the always-on, high-bandwidth, low-latency connection that defined the corporate office has now reached the vessel and the quayside. The convenience is real. So is the expanded attack surface.

Private 5G at Ports and Terminals

Private 5G (sometimes called non-public networks in 3GPP terminology) is being adopted at major container terminals and bulk ports because it offers the bandwidth, latency and device density needed for automation that industrial WiFi struggled to deliver reliably across a large open yard. A single terminal may run hundreds of connected devices: ship-to-shore crane sensors, rubber-tyred gantry crane control, automated guided vehicles, reefer monitoring, gate cameras, RFID readers and handheld terminals.

Each of these is an operational technology endpoint, and many of them now control or influence physical movement of heavy equipment. A compromised crane control channel is not an IT incident, it is a safety incident with the potential for serious injury or a dropped container. The private 5G core itself becomes critical infrastructure: the user plane function, the access and mobility management function, and the SIM provisioning and authentication systems are all high-value targets that a port operator must defend with the same rigour as a telecom carrier would.

Common findings in private 5G port assessments include default or weak credentials on the core network management interfaces, flat slicing where OT and IT share the same slice, SIM and subscriber data stored without adequate protection, exposed management planes reachable from the general yard network, and a lack of monitoring on the signalling plane where many 5G-specific attacks live. The IEC 62443 zones and conduits model maps cleanly onto a private 5G deployment, and applying it early avoids expensive re-segmentation later.

Network Slicing: Isolation or False Comfort

Network slicing is one of the headline security features of 5G. In principle, a single physical 5G network can be partitioned into multiple logical networks, each with its own performance characteristics and isolation boundary. A vessel or terminal could run one slice for safety-critical OT, a second for business IT, and a third for crew welfare, with traffic on each slice logically separated from the others.

In practice, slicing delivers isolation only when it is configured and verified correctly. The separation between slices depends on the correct configuration of the radio access network, the transport network and the 5G core, and on the policies that decide which devices and which traffic flows are admitted to which slice. A misconfigured slice, or a device that is mistakenly authorised onto the wrong slice, breaks the boundary silently. Worse, slicing can create a false sense of security where operators assume isolation exists because the architecture diagram shows separate slices, without ever testing that the boundary actually holds under adversarial conditions.

The practical guidance is to treat slicing as one control among several, not as a substitute for traditional segmentation. Safety-critical OT should sit in its own slice and behind its own firewall and access control. The slice boundary should be tested as part of any maritime VAPT engagement, with the tester attempting to cross from a crew or IT slice into the OT slice. Logging and monitoring of the signalling and control plane is essential because many slice-isolation failures are invisible at the application layer and only detectable in the network and signalling telemetry.

The Widened Vessel Attack Surface

When a vessel gains a persistent high-bandwidth 5G link, every weakness that was previously hard to reach becomes easier to reach. The most common single mistake is dropping a 5G router onto the existing vessel network without segmentation, so that the router provides a direct path from the public internet to whatever the vessel network already exposes. If that network is flat, or near-flat, the 5G modem effectively publishes the bridge and engine systems to anyone who can reach the modem.

Specific exposures that 5G amplifies include: unpatched ECDIS and engine-monitoring hosts that were tolerable when rarely reachable but become live targets when continuously online; satcom and now 5G modems with default credentials and exposed web management interfaces; vendor remote-diagnostic services that previously required scheduling around satcom availability and now run on demand; and crew bring-your-own-device traffic that can pivot toward higher-trust zones if the network is not properly partitioned.

There is also a subtler operational risk. Always-on connectivity changes crew behaviour. Software gets updated more casually, remote sessions are left open longer, and the discipline that scarce bandwidth used to enforce relaxes. The defensive answer is not to refuse 5G, which would be both impractical and commercially uncompetitive. The answer is to treat the 5G link as an untrusted external connection, terminate it at a hardened boundary, and apply the same segmentation, monitoring and access control that a shore enterprise would apply to its internet edge.

Securing the Maritime 5G Edge

Securing a maritime 5G deployment starts at the edge device. The 5G modem or router should be treated as an internet-facing firewall, not as a transparent bridge. That means a hardened configuration, no default credentials, management interfaces restricted to an engineering workstation, all unused services disabled, and firmware verified against the latest vendor advisory at every maintenance visit. Behind the edge device, the vessel network must be segmented so that the 5G link reaches only the zones that genuinely need shore connectivity.

A pragmatic segmentation model places the 5G and satcom links in a dedicated boundary zone, with explicit firewall rules controlling what each internal zone can reach through that boundary. Bridge OT, engine OT and cargo OT sit in the most restrictive zones and should not have direct outbound internet access at all. Where a vendor needs remote diagnostic access to an OT system, that access is gated through a hardened jump host with session recording, multi-factor authentication and time-limited authorisation, never through a permanently open path.

• Treat the 5G modem as an untrusted edge: hardened config, no defaults, restricted management plane, verified firmware
• Terminate the link in a boundary zone, never directly on the bridge or engine LAN
• Deny OT outbound internet by default: bridge, engine and cargo zones reach shore only through explicit, logged, allow-listed paths
• Gate vendor remote access through a recorded, MFA-protected jump host with time-limited sessions
• Separate crew welfare traffic at the VLAN and slice level, with firewall enforcement, not just a different SSID
• Monitor the link: log all boundary-crossing connections, watch for unexpected outbound destinations, feed telemetry to the maritime SOC

5G, IMO 2021 and the Risk Assessment

Adding a 5G link to a vessel is a change to its cyber risk profile, and under IMO Resolution MSC.428(98) that change must be reflected in the ship Safety Management System. A flag state or class auditor reviewing the vessel will expect to see the 5G link in the asset inventory, a documented risk assessment of the new connectivity, the controls applied to manage that risk, and any update to the incident response and contingency procedures that the new link implies.

The management-of-change discipline matters here. Connectivity tends to be added incrementally and informally, a router here, a new crew WiFi access point there, a vendor link enabled for a single voyage and never disabled. Each addition that is not captured in the asset inventory and risk assessment is a gap that an auditor or an attacker can find. The practical control is to require that any new connectivity, including 5G, passes through the same management-of-change process as any other modification to a safety-relevant system, with sign-off, documentation and an updated risk assessment.

Codesecure recommends that shipowners adopting 5G run a focused connectivity review that inventories every shore link across the fleet, assesses the segmentation behind each one, and produces an evidence pack that satisfies IMO 2021, BIMCO and the charterer security questionnaire in a single document. The same review feeds the maritime SIEM design, since the monitoring strategy must account for the new traffic the 5G link carries.