DNV said its dedicated ShipManager servers are now back online following a cyber-attack nine weeks ago.
The major classification society said its server environment had to be rebuilt after the attack in early January.
“While users are back online, the work to resume full scope of service is ongoing,” the Norwegian-headquartered organisation said.
DNV added that the “server outage did not impact any vessels’ ability to operate” as ships could still use the on-board offline functionalities of the software.
The classification society said no other systems on board were impacted as the ShipManager servers are isolated from the rest of DNV’s IT infrastructure.
Up to 1,000 ships, operated by 70 companies, were initially affected in the attack on the modular software that supports the management of vessels and fleets in technical, operational and compliance aspects.
The organisation said it continues to have a dialogue with all affected shipowners and operators, advising them to consider relevant mitigating measures depending on the types of data they had uploaded.
Cyber security sources said earlier that by breaking into a supply-chain linked system hackers could have the potential to target companies, from which they can try to extract payments.
DNV experts shut down the servers immediately in response to the attack on 7 January.
Norwegian police are still investigating the attack and have informed other police agencies.
The DNV attack followed one on navigation technology group Voyager Worldwide, which has more than 1,000 shipping customers, last December and led to systems being taken offline. Earlier, Danaos Management Consultants was also hit.
