Facebook 'eliminates most of porn image spam attack'

Facebook said it has rid its site of most of the pornographic and violent images posted as part of a spam attack, BBC News reported.

The social network blamed browser vulnerability and said it was improving its systems to defend itself against similar attacks in the future.

Thousands of the website's 800 million users have complained about the pictures over recent days.

A source told the BBC that Facebook knew who was responsible - and it was not an Anonymous hacktivist.

The firm is understood to be working with its legal department to take action against the suspected attacker.

Facebook said the spam attack worked via a "self-XSS vulnerability in the browser".

It added: "During this attack, users were tricked into pasting and executing malicious javascript in their browser URL bar causing them to unknowingly share this offensive content.

"No user data or accounts were compromised during this attack."

The firm said its engineers had built enforcement mechanisms to shut down malicious pages and accounts that attempt to exploit the vulnerability.

It also offered the following advice to help guard against further attacks:

• Never copy and paste unknown code into the address bar
• Always use an up-to-date browser
• Use the report links on Facebook to flag suspicious behaviour or content on friends' accounts

Facebook allows children above the age of 13 to be members, and polices a ban against inappropriate images.

However, security experts said it was difficult for the firm to respond to this threat, bearing in mind it exploited vulnerability in an unnamed web browser rather than the site itself.