Email messages that contain an April Fool's joke message may contain malware too.
Stonesoft has advised computer users to be cautious as April Fool's day is known to be a time when new data security threats arise and old ones are reactivated.
It claimed that on 1st April 2007, the ANI worm spread around the globe using an exploit found in Windows, and the same date in 2008, the Storm worm spread in email messages that were sent using April Fool's theme.
Olli-Pekka Niemi, vulnerability expert at Stonesoft, said: “The reason for data security threats to evolve around April Fool's day is quite understandable. Even if people receive email messages from unknown addresses they tend to open the greetings more easily in hope for a juicy April Fool's joke.
“The most important thing is to remember the basics. Make sure that all programs are up-to-date, especially the security programs, avoid surfing to unknown sites, opening messages or attachments from unknown addresses and in general behave according to your best knowledge.”