Computer security firms are warning about an attack that hijacks the clipboard where copied text is stored. The attack puts a hard-to-delete weblink into the clipboard that, if followed, leads people to a website selling fake security software. The code that inserts the link has been found in flash-based adverts seen on many legitimate websites. The attack on the clipboard has hit both Windows and Mac users of the Firefox web browser.
The attack has come to light as victims log reports in discussion forums of a weblink that appears in the clipboard in place of text they thought they had placed there.
It seems to work by exploiting Adobe Flash files used to make display adverts in such a way as to endlessly flush the clipboard of other text and constantly re-insert the malicious link in its place.