Capita, the UK-based provider of business process outsourcing solutions and professional support services, has admitted that pensions data was ‘likely’ stolen in a Russia-linked cyber attack earlier this year, reports The Telegraph. Capita has written to city clients saying that pensions data was likely ‘exfiltrated’ by Russian-speaking ransomware gang Black Basta during the cyber-incident in late March.

In a message sent to clients on Thursday, Capita said, “To be clear, this does not necessarily mean that your data has been identified as exfiltrated, it means that your data was on Capita servers from which some data is likely to have been exfiltrated.” This follows Capita’s internal investigation, which involved searching servers impacted by the hack to understand what data has been lost.

In its update last month, the group said that while the incident caused disruption to some services provided to individual clients, the majority of its client services remained in operation. The company was forced to backtrack following its suggestion that no data at all was stolen after sensitive information, including primary school vetting documents, appeared on the dark web. The outsourcer told clients that there is ‘no evidence’ pensions data is available on the dark web and has recruited a third-party specialist to monitor the situation. The company also said it has rebuilt its server systems to reduce the risk of another cyberattack. “Capita continues to work through its forensic investigations and inform any customers, suppliers or colleagues that are impacted in a timely manner,” the company stated. The investigation is expected to conclude by the end of next week.

Earlier this week, , the BBC reported that the UK’s Pensions Regulator has asked trustees responsible for funds that use Capita as an administrator to assess whether clients' data is at risk following the incident. Meanwhile, it was also reported that Deliveroo was forced to scrap an £18 million deal with Capita, after five months when it failed to deliver on its promise to recruit a team of 150 multilingual staff for the takeaway company.