May 2011 was marked by a number of Facebook survey scams trapping users with offers of free airline tickets; exclusive video footage of Osama Bin Laden’s death; and threat of rogue antivirus attacks, according to GFI Software.

Online scammers employed a number of lures to entice victims to participate in their surveys with offers of free merchandise to trick users into reposting messages to their Facebook wall, which then redirect their friends to the same surveys.

GFI said that those filling out the survey will be on the receiving end of high volumes of spam as any personal information they shared will be exploited by identity thieves, and their PCs will be infected with a broad range of malicious malware.

In addition, GFI also uncovered a viral spam attack on the popular microblogging site Tumblr. Spammers, taking advantage of the ease of Tumblr’s reblog feature, tricked users into reblogging a phony message meant to keep their account from being deactivated.

GFI has identified top 10 most prevalent malware threats for the month of May 2011 which revealed that the vast majority of malware threats found continue to be Trojans, mostly detected in generic form.

BT Trojan topped the list with 22.51%, cobra Trojan stood second with 3.79% while SB.0 Trojan posted 3.73%.

GFI Software senior threat researcher Christopher Boyd said surveys are an increasingly common tactic used to disguise a wide range of security threats lurking on Facebook and other social networking sites.

"Scammers also have improved their ability to immediately hijack high-profile news for their attacks and by exploiting breaking and developing news stories, they are catching users off guard," Boyd said.

"Users should always be wary of promises of free items or sensational content, and they should never share personal and financial information online unless they are dealing directly with a known, trusted and secure website not a Facebook or Twitter post claiming to represent a recognised business or organisation."