Facebook attacks that force users to unwittingly endorse scam pages keep spreading, researchers say.
When the exploits surfaced on Tuesday, they resulted in hundreds of thousands of users giving their thumbs up to links with titles including: "LOL This girl gets OWNED after a POLICE OFFICER reads her STATUS MESSAGE." Since then, similar attacks have circulated that cause users to recommend pages promising naked pictures of alternative rock diva Hayley Williams or the phone number of heart-throb singer Justin Bieber.
The attacks exploit a flaw present in virtually every browser that allows unscrupulous webmasters to control the links a visitor clicks on. They work by overlaying an invisible iframe or other web object on top of a link or blank space on a webpage. The result is that a user can never be sure he's clicking on the link or button he thinks he is. The exploit has been coined “clickjacking” by Jeremiah Grossman and Robert “RSnake” Hansen, the security researchers who brought the technique to public awareness in late 2008.
So far, there are no reports that the Facebook attacks amount to much more than pranks that cause users to click a “Like” button that recommends a link to their friends. But it's not inconceivable that the “likejacking” exploits could be used in much the way black-hat search engine optimization is used to lure people to websites that try to install malware on their machines.
There's only so much Facebook can do to stop the exploits since the actual clickjacking takes place on websites controlled by the attackers. Still, engineers could probably do better at isolating and then blocking the users or bots that are perpetuating the scam. Until then, remember that the number of “Likes” an ad or other piece of content boast on Facebook is largely meaningless. ®