(Image Source: Sky News)

BY ADAM FALK
ANCHOR MEGAN MURPHY

Facebook is cleaning up users news feeds after a coordinated spam attack hit the site over the last few days. ABC has more on the kinds of graphic images users saw.

REPORTER: “The images are shocking - raw porn. Sickening - wounded animals. Startling - Photoshoped image of Justin Bieber. The pictures have been popping up in Facebook news feeds, maybe thousands in the last few days.”

ZDNet reported Wednesday-- Facebook has “eliminated” the attack. The cause? The social site says it was a browser flaw that allowed cross-site scripting. That basically lets the attacker execute JavaScript that can control the website you’re visiting.

Sources say the virus spread through malicious links. Facebook claims it knows who started it, but it’s not naming names.

The BBC has debunked one theory-- that hacktivist group Anonymous launched the virus for Guy Fawkes Day, November 5th.

ZDNet suggests it might take a while, but Facebook will charge the person responsible.

“Three months ago, Spam King Sanford Wallace surrendered to the FBIafter...spamming Facebook. It took over two years, but Facebook eventually put him in his place. Let’s hope the company manages to do it again for this attack.”

Usually, in a hack like this, the hackers stand to gain something - typically cash. But a Sophos security expert writes...

“This seems to be a purely malicious act. Facebook has a reputation for maintaining a reasonably family friendly environment”

Although the company says the hack is behind us, remember -- to avoid spam,  never copy and paste unknown code, keep your browser up to date and flag false links.

Transcript by Newsy.