If users who follow the link then click to play what purports to be video coverage of the attack, they are prompted to update their Adobe Flash player with a pop-up window that looks very much like the real thing. Those who accept the prompt unwittingly install malware on their computers.
Within three hours of the scam's first appearance, more than 60,000 users had followed a link to the spoofed CNN page, according to Sophos Senior Security Advisor Chester Wisniewski. Facebook removed that link, but others are still being shared.
"The bad guys are rotating through scam pages trying to stay ahead of Facebook," Wisniewski said.
In a statement, Facebook said it was "in the process of cleaning up this spam now, and remediating any affected users."
A representative status update shown in a screenshot on the Sophos blog reads, "U.S. Attacks Iran and Saudia Arabia. F**k :-( [LINK] The Begin of World War 3?"
Users who accepted the Flash player update prompt installed a fake antivirus tool on their computers. That tool would then alert them that their computer is infected with malware that can be eliminated for a fee. Such scams are one of the most lucrative, Wisniewski said, noting the irony that they net far more money than the legitimate security products Sophos and other security companies peddle.
In addition to a healthy dose of skepticism that the U.S. would attack its ally Saudi Arabia, Facebook users can avoid the scam and others like it by updating Flash only from Adobe's own website rather than from pop ups.
Updated 2/3/12 at 5:42 p.m. with response from Facebook