Researchers recently spotted a hacker named Kirllos selling Facebook user names and passwords in an underground hacker forum, but what really caught their attention was the volume of credentials he had for sale: 1.5 million accounts.

However they are not sure if those accounts for sale are legitimate. If they are legitimate, he has the account information of about one in every 300 Facebook users!!

The price varies from $25 to $45 per 1,000 accounts, depending on the number of contacts each user has.

Facebook has more than 400 million users worldwide, many of whom fall victim to scams each day.

In one such scam, criminals sent out messages from a compromised account, telling friends that the account's owner is trapped in a foreign country and needs money to get home. In another, they sent links that lead to malicious software, telling friends that it's a hilarious or sensationalistic video.

Ref: http://www.computerworld.com/s/article/9175936/1.5M_stolen_Facebook_I...
Ref: http://economictimes.indiatimes.com/infotech/software/15-mn-Facebook-...