Faceboook’s legal team are hot on the tail of those people responsible for a spam attack of hardcore porn and violent images which flooded the social networking site and spread like a virus earlier this week

Since Tuesday, graphic images have cropped up on some users’ pages, including hardcore porn photos, a photoshopped, nude image of Justin Bieber engaged in a sexual position, a naked grandma and an abused dog. Some users were said to be “distraught.”

Bieber subject of fake celebrity porn spam on Facebook

Facebook spokesman Andrew Noyes said that users were ''tricked into pasting and executing malicious Javascript in their browser URL bar, causing them to unknowingly share this offensive content''.

The flow of images has since been stemmed, though its reputation as a family-friendly social network is likely to be affected. Facebook said: ''We've built enforcement mechanisms to quickly shut down the malicious pages and accounts that attempt to exploit it.''

Users affected will be contacted by Facebook in due course with information of how to protect themselves from such attacks.

"The incident underlines the importance of considering your actions and the possible unintended consequences when using sites like Facebook. Users should never enter unknown software code into the address bar and routinely update the web browser they use," warned internet security expert, Sophos.