Online deals service LivingSocial is the latest company to report a breach of its computer systems that may mean attackers accessed customer details.
At the weekend, the company confirmed that more than 50 million accounts were potentially affected by the cyber attack.
According to LivingSocial, names, email addresses, dates of birth and encrypted passwords could have been compromised, said US reports.
However, the company said the database of credit card information was not accessed or affected.
Although passwords were encrypted, the company has reset all affected users’ passwords as a security precaution.
LivingSocial said it is working with law enforcement officials to investigate the attack and has contacted customers in most countries to warm them of the potential breach.
The company has warned users to be on the lookout for phishing emails as a result of the breach.
"Please note that LivingSocial will never ask you directly for personal or account information in an email," the company said in its notification to customers.
“Please disregard any emails claiming to be from LivingSocial that request such information or direct you to a different website that asks for such information,” the notification said.
In an email to employees, LivingSocial chief executive Tim O'Shaughnessy said the company is "redoubling efforts to prevent any issues in the future”, according to other reports.