A website that lists 1.5 million compromised Facebook accounts for sale has been discovered by iDefense Labs of Verisign. Each 1,000 accounts with not more than 10 friends are for sale for $25 and $45 for 1,000 accounts for those with more than 10 friends.

According to the researchers, another path is the malware spreading through compromised user's friend network.

PC World stated that the information was posted by a hacker on a Russian forum. The accounts consist of around four tenths of the percentage of the entire Facebook user base which is approximately 400 million.

Facebook is unable to estimate the number of accounts that may be compromised by other hackers. A spokesperson Andrew Noyes added that the social networking site is incessantly keeping an eye for suspicious activity and taking necessary action.

Any user account that is suspected being compromised and detected by Facebook is suspended. The particular user is then required to take steps to confirm that the account is secure.

Thus, Facebook users should always be cautious of adding people they do not directly know, and make certain that their privacy settings are set to protect their personal information.