Betting firm Paddy Power has revealed that it is contacting 649,055 customers who were affected by a cyber attack on its IT systems four years ago.
It said that no financial information or passwords were compromised in the "isolated" incident, and insisted that customers' accounts were not at risk. However, the dataset that was hacked contained individual customer names, usernames, addresses, email addresses, phone numbers, dates of birth and prompted questions and answers.
"The accessed information alone would not have been sufficient to grant access to a Paddy Power customer account and this incident has no impact on customers who opened accounts after 2010," the betting firm said yesterday.
"Paddy Power's account monitoring has not detected any suspicious activity to indicate that customers' accounts have been adversely impacted in any way."
Nonetheless, Paddy Power has advised affected customers to review other sites where they have used the same prompted question and answer as a security measure, and to update the information where appropriate.
Paddy Power said it was 'advised' in May 2014 of an allegation that an identified individual in Canada had possessed a historical customer dataset belonging to the company.
After verifying a sample of the data, the firm sought and received two court orders in Canada to seize the individual's IT assets, to recover the dataset and delete it from the IT systems, to examine his bank accounts and financial transactions and to question him.
Although Paddy Power had detected the cyber attack in 2010, and carried out an investigation to determine that no financial information or customer passwords were put at risk, it suspected that some non-financial customer data may have been exposed. This led to a full review of its security systems.
Peter O'Donovan, MD Online, Paddy Power apologised to customers for the breach and said that the company has invested over 4 million in its IT security systems in recent years.
He said: "Robust security systems and processes are critical to our business and we continuously invest in our information security systems to meet evolving threats. This means we are very confident in our current security systems and we continue to invest in them to ensure we have best in class capabilities across vulnerability management, software security and infrastructure."
The company said it has notified the Office of the Data Protection Commissioner in Ireland of the incident.
An IT security expert at information security technology provider Clearswift said that Paddy Power should have been more transparent at the time the data breach occurred.
"[Yesterday's] announcement of a massive data breach at Paddy Power, with personal details of over 640,000, nearly a third of its customers having been stolen, is of a huge concern due to the company's failure to publicly disclose the attack, having allegedly had knowledge of it since 2010," said Maksym Schipka, SVP of engineering at Clearswift.
"A breach on this scale, combined with the lack of transparency demonstrated by the company will certainly affect its professional reputation."
He added: "The statement from the company informing the public that the company is very confident in their current security systems may still point at a lack of understanding of the complexities and sophistication of modern cybercriminals. [The systems] require adequate critical information protection solutions in place, underpinned by a well thought-through set of policies and processes that are regularly reviewed and tested."