Finastra has powered up servers that were brought offline at the tail-end of last week following a possible ransomware attack.
Finastra on Friday informed customers of a "potential security breach", warning that "we are anticipating some disruption to certain services, particularly in North America".
With servers offline, the company closed some offices in Canada and London, and brought in an independent forensic firm to investigate the scope of the incident.
In a statement issued Sunday evening, chief operating officer Tom Kilroy says the firm is beginning to bring its servers back online after neutralsing the threat posed by the attack.
"We are working with our impacted customers systematically and securely to return to normal operations,." he writes. "Because our solutions each have their own nuanced processes to move from being available to operationally live, each of our products will be back once readiness steps are completed."
The statement continues: "We would like to reassure our stakeholders that, to the best of our knowledge, we do not believe that any customer or employee data was accessed or exfiltrated, nor do we believe our clients’ networks were impacted."