The latest in a series of viral attacks on Facebook take advantage of slack policing of new applications to exploit users' trust in the prominent social networking website.
Five separate security problems have hit the site over the last week. As well as four new applications which try to steal information from users' profiles, a variation on the "Koobface" virus is reported as seeing a resurgence of activity.
The virus, first seen in December 2008, targets users by claiming they need to download a plugin to view a video sent to them by a friend, when it in fact installs a piece of malware which could be used to allow a hacker to take control of infected computers. It also reads any stored login details on infected computers and uses the information to send itself to user's contacts on a range of social networking websites including MySpace and Bebo.
The four Facebook applications which have concerned security experts over the last week have led commentators to criticise the company's laissez-faire approach to the vetting of new utilities on the site. While the rogue applications do not directly harm a user's computer, they can be used to steal users' data.
"There will occasionally be some applications that people don't like," site co-founder Mark Zuckerberg told the BBC's Newsbeat. "Our philosophy is that having an open system anyone can participate in is generally better."