Aflac, one of the largest insurance company in the US, has over 50 million customers worldwide and around 15m in America.

The breach identified on June 12 was carried out by a yet unknown hacking group that accessed files containing Social Security numbers, health claims and other private data.

A 11 class-action lawsuits have been already filed against the company, accusing it of failing to protect user data.

Aflac confirmed the breach in a statement filed with the US Securities and Exchange Commission on Friday, noting that the incident affected customers, beneficiaries, employees and agents.