Hackers have stolen the user names and e-mail addresses of 20 million members of a Russian dating website and offered the information for sale online, according to a Web security company.
Easy Solutions, the fraud-detection software-maker who unearthed the breach, did not identify the hacked website in its online statement, but the Bloomberg news agency said it was a St. Petersburg-based site called Topface.
Topface CEO Dmitry Filatov said the company had no proof of the breach but was investigating, the report said.
"The list [of web credentials stolen by the hackers] appears to be international in nature with hundreds of domains listed from all over the world," Daniel Ingevaldson, chief technology officer at Easy Solutions, said in his company's statement.
The largest chunks of web credentials used by people who logged in to the dating website are from Hotmail, Yahoo and Gmail, Ingevaldson said.
Hackers will use stolen credentials to try and access bank accounts and e-mails by exploiting online users' tendency to select the same password for various websites, he added.
Fifty percent of the hacked credentials belonged to people based in Russia and 40 percent came from the European Union, Bloomberg reported.