Mediterranean Shipping Co has confirmed it was the victim of a cyber attack over the Easter holiday weekend
But the Swiss boxship and cruiseship operator said the impact on operations was limited.
The company put its website and myMSC service back online on 15 April after taking them offline as a precaution a week ago.
MSC had previously said there had been a possible malware attack, but has now revealed this was indeed the case.
The attack was confined to its Geneva headquarters.
"After a thorough investigation, we confirmed that it was confined to a limited number of physical computer systems in Geneva only and we determined that it was a malware attack based on an engineered targeted vulnerability," the groups said in an update.
"We have shared as per industry standards the malware with our technology partners so that mitigations could be made available not only to us."
The company added that it will not be commenting further in detail, as this would be counter-productive from a security perspective.
"If in due time we feel that there are any important lessons or best practices to learn, we will share information via the appropriate industry forum or directly with other companies," MSC said.
Staff stuck at home
The coronavirus outbreak meant many staff were working from home, so "it took a bit of time to sort things out," MSC admitted.
"It was very important to us to ensure that we had a validated solution in place and to cover off all necessary checks and testing before making the website live again and that this would not pose any risk, even if unlikely, to any of our customers or partners."
MSC said it is not aware of any lost or compromised data.
The company added it was not complacent and remained focused and cautious in its approach to information technology.
The liner giant brought in external experts to help with the Easter issue.
"We actively decided as a precaution to take our headquarters computer systems offline in order to ensure their integrity," the operator added.
MSC stressed it follows all the necessary security protocols in all communications and business transactions.
'Confidential measures'
"In addition to these specific protocols, we have other confidential measures and processes in place, such as regular cyber-security training for employees on shore and at sea," the company said.
The outfit also said it was involved in the "continuous evolution" of internal IT systems.
MSC is a founding member of the Digital Container Shipping Association, a non-profit industry group which is working on supporting companies in cyber risk management.
The Swiss company, which operates 471 vessels, had kept in touch with customers on Twitter during the outage, and assured them bookings could still be made through its Inttra platform and calls to its offices.
On Tuesday, Danish pump maker DESMI said it would not succumb to blackmail by hackers who attacked its IT systems overnight on 9 April and demanded money to allow recovery of stolen data.
“Under no circumstances” will he pay a ransom, DESMI chief executive Henrik Sorensen said.
In November, London tanker owner James Fisher was the victim of an attack, more than two years after a high-profile NotPetya onslaught hit Maersk's digital network at a cost of $300m.
