The daily-deal site LivingSocial suffered a security breach Friday that affected 50 million customers.
Cybercriminals accessed encrypted passwords, names, emails and dates of birth, according to an internal memo emailed to employees.
However, it said, neither customer credit card information nor merchant banking information was compromised.
(Read More: A 12-Year-Old Could Hack Most Companies: Expert)
"We recently experienced a cyber-attack on our computer systems that resulted in unauthorized access to some customer data from our servers," LivingSocial CEO Tim O'Shaughnessy said in the email. "We are actively working with law enforcement to investigate this issue."