Facebook users have been bombarded with explicit and violent images in the latest malware campaign aimed at the giant social networking site, a security researcher said today.

The company confirmed the attack and said it had "dramatically limited the damage" and was on the trail of those responsible.

"For the last 24 hours, many people have reported seeing highly-offensive images on their Facebook news feeds," said Graham Cluley, a senior technology consultant at antivirus vendor Sophos, in an interview early Tuesday.

"But exactly how those images got there and what cause them to appear, is still somewhat of a mystery," Cluley added.

Cluley speculated that the attack may have been based on "clickjacking," which describes a type of attack where hackers plant invisible "buttons" on a website page. When a user clicks on the overlaying page component, they actually execute malicious code or script that can hijack their browser or personal computer.

Cluley also said it was possible that previous-planted malware conducted the Facebook spam campaign.

Full story: Computerworld