There has been an increase in cases where digital identity manipulation has been occurring, giving rise to what is being described as “zombie” vessels.
This practice, which has been in use for several years, involves the emulation/adoption of physical, digital or registered identifiers associated to a vessel that is no longer in circulation.
A vessel tracking system dependent upon AIS essentially collects positions based on the static and dynamic messages associated to a MMSI — think of this as a telephone number issued by the flag that a vessel is registered to. The flag will provide a radio license, detailing digital identifiers such as MMSI and call sign.
Hypothetically, only one MMSI ought to be assigned as in use by any vessel at any time, however MMSIs can be recycled/reissued by flags, AIS transponders can be “cracked” to manipulate digital identifiers giving the impression of multiple targets or historically active targets, as well as erroneous use, or message corruption may occur causing some challenges to the collection process. As such, companies that make use of AIS typically have a cleaning/identity association process to resolve some of these issues and validate targets.
When looking at a 30-day analysis period, out of the 573,123 unique MMSI targets seen, 11% are nonship MMSIs, 17% are associated to the Market Intelligence ships database and 72% are unmatched vessel MMSI targets.
Within the 72% of unmatched vessel MMSI targets, some were still transmitting identifiers, allowing us to further classify them into typologies, including cargo vessels (18%), fishing vessels (16%), pleasure crafts (16%), sailing vessels (14%) and tankers (1.4%), which would not necessarily qualify under the IMO number scheme based on their characteristics and operations.
‘Use of “zombie” ships’ is one of the case studies in Maritime State of Play report 2025.
The report provides context and foundational knowledge toward maritime operational subterfuge tactics, as well as deceptive shipping tactics to support compliance, defense and national security functions, enhance due diligence frameworks and broaden investigation processes.
Key insights from the report include:
- Record-high sanctions on vessels and their associates.
- Increasing use of deceptive tactics to evade sanctions.
- Enhanced technology fueling sophisticated subterfuge operations.
- Rising complexity in identifying beneficiaries due to deceptive practices.
