The viral giraffe riddle game is fake and is designed by hackers to gain unauthorized entry to users' accounts, according to latest posts in Facebook.

What seemed to be a fun and exciting game in social media turned out to be a hoax and is designed to hack accounts of users who take on the challenge.

According to reports, hacker group Anonymous designed the giraffe riddle game in Facebook to obtain users' email and password once they change their default photo.

The post also added that the giraffe challenge was the group's cleansing program. The "cleansing program" involved wiping out bank accounts and hard drives of FB users with giraffe profile pics.

"A few of my FB friends have already had it happen, so change your pics back!!!!," the particular post even claimed.

New notifications are also circulating online warning Facebook users not to join the giraffe riddle game or be careful in changing their profile pictures.

The warning said that a virus exploits the recently discovered JPEG vulnerability spreading over Google's images of giraffes.

"It's been done in the past, but with HTML code instead of the JPEG. It is a virus, but it didn't spread very far. We've only had two reports of it," said chief technical officer for SANS' Internet Storm Center James Thompson.

"When you do it, Facebook automatically gives the hackers your user mail and password, malicious code embedded in the JPEG image gives the hackers everything they need," said to Mr. Thompson.

The blog added that Microsoft and Google are working on the virus and JPEG vulnerability. Facebook users are recommended NOT to change their profile pictures to giraffes.

Last Saturday, many Facebook users suddenly change their profile pictures to a photo of a giraffe. It was found out that they got the wrong answer to the viral quiz.

"3:00 am, the doorbell rings and you wake up. Unexpected visitors. It's your parents and they are there for breakfast. You have strawberry jam, honey, wine, bread and cheese. What is the first thing you open?," went the viral giraffe riddle.

However, according to a blog explaining the process of changing profile pictures, changing a profile picture to an image of a giraffe is not going to give hackers a user's password. It will also not make FB users targets for hackers.

However, users must be careful where they get the photo of the giraffe that they use. Netizens should make sure that the photo was not obtained from malicious Web sites.