A surge in spam has been predicted this year on social networking sites like Facebook, according to a new report.

In its 2009 Annual Security Report, the networking company Cisco, said that worldwide spam volumes will increase by 30 or 40 percent over 2009 levels.

Spammers currently send out up to 100 million junk e-mails a day and, although the vast majority are never opened, enough people click on the links to make spam a multimillion-dollar industry.

One of the most notorious spam attacks on Facebook was Koobface, a malware bot that commandeered Facebook profiles and turned them into infectious zombies.

Koobface fooled online victims by posing as Facebook friends, which increased the chances that people would follow malicious links.

Spammers are trying to establish trust and they see Facebook as the way in, Matthew Prince, co-creator of Project Honey Pot and a professor of cyberlaw at the John Marshall Law School in Chicago, told the Times Online.

Prince explained that schemes can be as old-fashioned and predictable as hackers abusing network profiles to pretend that they are stuck in jail and need money for bail.

According to Prince, cyber criminals are capable of accessing online identities by deploying password hacking software that processes millions of variants of everyday words in just a few minutes.