Since 2017, all of the four biggest container shipping companies (APM-Maersk, COSCO, MSC and CMA CGM) and the IMO have been hit by cyberattacks. The shipping industry is considered to be a vulnerable and highly lucrative target, with maritime companies' shore-based networks particularly exposed to ransomware. The 'NotPetya' malware cyberattack on Maersk in 2017, which reportedly cost the company around US$300 million, highlighted the opportunity for cybercriminals to bring a critical industry down, meaning payment of a ransom was perhaps more likely than other industries. Shipowners and operators should be aware that traditional marine insurance products might not cover all the risks of cyber incidents.