"Status jacking,'' which involves the theft of login information so that hackers can post malicious messages on the profile of users, is the latest security problem that threatens social networking Web sites.

The most active users on social networking Web sites, students aged 18 and 25, are most at risk of the problem because they are the most likely to share computers.

Online security company AVG looked into the safety measures within 50 global social networks. The research finds that there are almost 20,000 compromised web pages on 50 of the most popular social networks around.

The world's largest social networking site, Facebook, was found to contain more than half of the compromised sites found, while more than 7000 were on YouTube.

Peter Cameron, managing director for AVG Australia and New Zealand, said that it is necessary to raise the awareness on security issues on social networking sites among young people.

''The fact that AVG found almost 20,000 compromised web pages on the world's most popular social networking sites should make social media users sit up and take notice,'' Cameron said.

The study also finds that people aged 18 to 25 year olds are the least concerned when it comes to Internet security.

A recent British study shows that only 15 per cent of people aged 16 to 24 year olds are concerned about internet security. The figure is lower that the 23 per cent rate for the general population.