Russia-based cybercriminals are offering to sell 81,000 Facebook profiles after being hacked into them.
The hackers tried to sell the accounts online for only eight cents (10 cents) per profile.
They published private messages from the vulnerable accounts to encourage people to buy.
Many of the users whose details have been compromised are based in Ukraine and Russia – but some come from Britain, the US, Brazil and other countries.
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Facebook accounts in the UK are among the 81,000 profiles sold after being hacked by Russian cyber criminals. Cyber criminals use private messages from compromised accounts to advertise the profiles
Examples of the published news included an intimate chat between two lovers, grievances about a son-in-law, photos of a recent vacation sent between two Facebook friends, and a chat about a recent concert by Depeche Mode
According to the BBC Russian Service, the perpetrators indicate data from a total of 120 million accounts.
Facebook said its security was not compromised and that the data was probably obtained through malicious browser extensions.
The social media giant assured users that they have taken steps to prevent further accounts from being affected.
"We've contacted browser makers to make sure known malicious extensions in their stores are no longer available for download," said Facebook manager Guy Rosen to the BBC.
"We also contacted law enforcement and worked with local authorities to remove the Facebook-enabled website where information is displayed."
Just weeks after Facebook found a massive security breach on 50 million user accounts, the news became public. But the social media giant said it was not his fault in this case
The breach of data was first picked up in September when a user named FBSaler began publishing "personal information from 120 million Facebook users" in an English-language Internet forum.
The BBC survey found that more than 81,000 profiles advertised online contained private messages.
Sensitive information from another 176,000 accounts has also been released – although some information, such as email addresses and phone numbers, may come from users who did not hide it.
The IP address of one of the websites selling the data was traced back to St. Petersburg.
Its IP address was also used to propagate the LokiBot Trojan, giving attackers access to user passwords.
HOW CAN YOU RECOGNIZE WHEN YOUR FACEBOOK ACCOUNT HAS BEEN PLAYED BY HACKERS?
Facebook said that 30 million users were affected when it came to a data breach at the end of September.
This is a significant decline from the original estimate of 50 million users.
In addition to this update, 15 million users of the 30 million users were called up by hackers with names and contact information. Some 14 million people stole this information, along with a variety of other data, including username, date of birth, gender, and 15 of their recent searches.
The social media giant has launched its own website to check if you've been hit by the hack.
To see if you have been hacked:
- Visit the Facebook Help link after signing in to your Facebook account.
- Scroll down to the header section: "Is my Facebook account affected by this security issue?"
- The users receive an answer with "Yes" or "No". For unaffected users, no immediate action is required.
- For affected users, Facebook provides users with a list of data that they believe has been accessed by hackers.
- Affected users can tell if they've been part of the 15 million users whose names and contact information have been accessed, or of the 14 million that have been retrieved for more comprehensive information.
- You can also be part of the 1 million users whose access token was stolen, but no personal information was retrieved.
- Users should receive a "customized message" in the next few days to learn more about how to protect their account.